class Sequel::Dataset

A dataset represents an SQL query, or more generally, an abstract set of rows in the database. Datasets can be used to create, retrieve, update and delete records.

Query results are always retrieved on demand, so a dataset can be kept around and reused indefinitely (datasets never cache results):

my_posts = DB[:posts].where(:author => 'david') # no records are retrieved
my_posts.all # records are retrieved
my_posts.all # records are retrieved again

Most dataset methods return modified copies of the dataset (functional style), so you can reuse different datasets to access data:

posts = DB[:posts]
davids_posts = posts.where(:author => 'david')
old_posts = posts.where('stamp < ?', Date.today - 7)
davids_old_posts = davids_posts.where('stamp < ?', Date.today - 7)

Datasets are Enumerable objects, so they can be manipulated using any of the Enumerable methods, such as map, inject, etc.

For more information, see the “Dataset Basics” guide.

Constants

OPTS
TRUE_FREEZE

Whether #freeze can actually freeze datasets. True only on ruby 2.4+, as it requires clone(freeze: false)

1 - Methods that return modified datasets

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Constants

COLUMN_CHANGE_OPTS

The dataset options that require the removal of cached columns if changed.

CONDITIONED_JOIN_TYPES

These symbols have _join methods created (e.g. inner_join) that call join_table with the symbol, passing along the arguments and block from the method call.

EXTENSIONS

Hash of extension name symbols to callable objects to load the extension into the Dataset object (usually by extending it with a module defined in the extension).

JOIN_METHODS

All methods that return modified datasets with a joined table added.

NON_SQL_OPTIONS

Which options don't affect the SQL generation. Used by simple_select_all? to determine if this is a simple SELECT * FROM table.

QUERY_METHODS

Methods that return modified datasets

UNCONDITIONED_JOIN_TYPES

These symbols have _join methods created (e.g. natural_join). They accept a table argument and options hash which is passed to join_table, and they raise an error if called with a block.

Public Class Methods

register_extension(ext, mod=nil, &block) click to toggle source

Register an extension callback for Dataset objects. ext should be the extension name symbol, and mod should either be a Module that the dataset is extended with, or a callable object called with the database object. If mod is not provided, a block can be provided and is treated as the mod object.

If mod is a module, this also registers a Database extension that will extend all of the database's datasets.

# File lib/sequel/dataset/query.rb, line 53
def self.register_extension(ext, mod=nil, &block)
  if mod
    raise(Error, "cannot provide both mod and block to Dataset.register_extension") if block
    if mod.is_a?(Module)
      block = proc{|ds| ds.extend(mod)}
      Sequel::Database.register_extension(ext){|db| db.extend_datasets(mod)}
    else
      block = mod
    end
  end
  Sequel.synchronize{EXTENSIONS[ext] = block}
end

Public Instance Methods

_clone(opts = OPTS)

Save original clone implementation, as some other methods need to call it internally.

Alias for: clone
and(*cond, &block) click to toggle source

Alias for where.

# File lib/sequel/dataset/query.rb, line 67
def and(*cond, &block)
  where(*cond, &block)
end
clone(opts = OPTS) click to toggle source

Returns a new clone of the dataset with the given options merged. If the options changed include options in COLUMN_CHANGE_OPTS, the cached columns are deleted. This method should generally not be called directly by user code.

Calls superclass method
# File lib/sequel/dataset/query.rb, line 87
def clone(opts = OPTS)
  c = super(:freeze=>false)
  c.opts.merge!(opts)
  unless opts.each_key{|o| break if COLUMN_CHANGE_OPTS.include?(o)}
    c.clear_columns_cache
  end
  c.freeze if frozen?
  c
end
Also aliased as: _clone

2 - Methods that execute code on the database

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Constants

ACTION_METHODS

Action methods defined by Sequel that execute code on the database.

COLUMNS_CLONE_OPTIONS

The clone options to use when retriveing columns for a dataset.

Public Instance Methods

<<(arg) click to toggle source

Inserts the given argument into the database. Returns self so it can be used safely when chaining:

DB[:items] << {:id=>0, :name=>'Zero'} << DB[:old_items].select(:id, name)
# File lib/sequel/dataset/actions.rb, line 26
def <<(arg)
  insert(arg)
  self
end
[](*conditions) click to toggle source

Returns the first record matching the conditions. Examples:

DB[:table][:id=>1] # SELECT * FROM table WHERE (id = 1) LIMIT 1
# => {:id=1}
# File lib/sequel/dataset/actions.rb, line 35
def [](*conditions)
  raise(Error, ARRAY_ACCESS_ERROR_MSG) if (conditions.length == 1 and conditions.first.is_a?(Integer)) or conditions.length == 0
  first(*conditions)
end
all(&block) click to toggle source

Returns an array with all records in the dataset. If a block is given, the array is iterated over after all items have been loaded.

DB[:table].all # SELECT * FROM table
# => [{:id=>1, ...}, {:id=>2, ...}, ...]

# Iterate over all rows in the table
DB[:table].all{|row| p row}
# File lib/sequel/dataset/actions.rb, line 48
def all(&block)
  _all(block){|a| each{|r| a << r}}
end
avg(arg=Sequel.virtual_row(&Proc.new)) click to toggle source

Returns the average value for the given column/expression. Uses a virtual row block if no argument is given.

DB[:table].avg(:number) # SELECT avg(number) FROM table LIMIT 1
# => 3
DB[:table].avg{function(column)} # SELECT avg(function(column)) FROM table LIMIT 1
# => 1
# File lib/sequel/dataset/actions.rb, line 59
def avg(arg=Sequel.virtual_row(&Proc.new))
  _aggregate(:avg, arg)
end
columns() click to toggle source

Returns the columns in the result set in order as an array of symbols. If the columns are currently cached, returns the cached value. Otherwise, a SELECT query is performed to retrieve a single row in order to get the columns.

If you are looking for all columns for a single table and maybe some information about each column (e.g. database type), see Database#schema.

DB[:table].columns
# => [:id, :name]
# File lib/sequel/dataset/actions.rb, line 72
def columns
  _columns || columns!
end
columns!() click to toggle source

Ignore any cached column information and perform a query to retrieve a row in order to get the columns.

DB[:table].columns!
# => [:id, :name]
# File lib/sequel/dataset/actions.rb, line 81
def columns!
  ds = clone(COLUMNS_CLONE_OPTIONS)
  ds.each{break}

  if cols = ds.cache[:_columns]
    self.columns = cols
  else
    []
  end
end
count(arg=(no_arg=true), &block) click to toggle source

Returns the number of records in the dataset. If an argument is provided, it is used as the argument to count. If a block is provided, it is treated as a virtual row, and the result is used as the argument to count.

DB[:table].count # SELECT count(*) AS count FROM table LIMIT 1
# => 3
DB[:table].count(:column) # SELECT count(column) AS count FROM table LIMIT 1
# => 2
DB[:table].count{foo(column)} # SELECT count(foo(column)) AS count FROM table LIMIT 1
# => 1
# File lib/sequel/dataset/actions.rb, line 103
def count(arg=(no_arg=true), &block)
  if no_arg && !block
    cached_dataset(:_count_ds) do
      aggregate_dataset.select{count{}.*.as(:count)}.single_value_ds
    end.single_value!.to_i
  else
    if block
      if no_arg
        arg = Sequel.virtual_row(&block)
      else
        raise Error, 'cannot provide both argument and block to Dataset#count'
      end
    end

    _aggregate(:count, arg)
  end
end
delete(&block) click to toggle source

Deletes the records in the dataset. The returned value should be number of records deleted, but that is adapter dependent.

DB[:table].delete # DELETE * FROM table
# => 3
# File lib/sequel/dataset/actions.rb, line 126
def delete(&block)
  sql = delete_sql
  if uses_returning?(:delete)
    returning_fetch_rows(sql, &block)
  else
    execute_dui(sql)
  end
end
each() { |call| ... } click to toggle source

Iterates over the records in the dataset as they are yielded from the database adapter, and returns self.

DB[:table].each{|row| p row} # SELECT * FROM table

Note that this method is not safe to use on many adapters if you are running additional queries inside the provided block. If you are running queries inside the block, you should use all instead of each for the outer queries, or use a separate thread or shard inside each.

# File lib/sequel/dataset/actions.rb, line 144
def each
  if rp = row_proc
    fetch_rows(select_sql){|r| yield rp.call(r)}
  else
    fetch_rows(select_sql){|r| yield r}
  end
  self
end
empty?() click to toggle source

Returns true if no records exist in the dataset, false otherwise

DB[:table].empty? # SELECT 1 AS one FROM table LIMIT 1
# => false
# File lib/sequel/dataset/actions.rb, line 157
def empty?
  cached_dataset(:_empty_ds) do
    single_value_ds.unordered.select(Sequel::SQL::AliasedExpression.new(1, :one))
  end.single_value!.nil?
end
first(*args, &block) click to toggle source

If a integer argument is given, it is interpreted as a limit, and then returns all matching records up to that limit. If no argument is passed, it returns the first matching record. If any other type of argument(s) is passed, it is given to filter and the first matching record is returned. If a block is given, it is used to filter the dataset before returning anything.

If there are no records in the dataset, returns nil (or an empty array if an integer argument is given).

Examples:

DB[:table].first # SELECT * FROM table LIMIT 1
# => {:id=>7}

DB[:table].first(2) # SELECT * FROM table LIMIT 2
# => [{:id=>6}, {:id=>4}]

DB[:table].first(:id=>2) # SELECT * FROM table WHERE (id = 2) LIMIT 1
# => {:id=>2}

DB[:table].first("id = 3") # SELECT * FROM table WHERE (id = 3) LIMIT 1
# => {:id=>3}

DB[:table].first("id = ?", 4) # SELECT * FROM table WHERE (id = 4) LIMIT 1
# => {:id=>4}

DB[:table].first{id > 2} # SELECT * FROM table WHERE (id > 2) LIMIT 1
# => {:id=>5}

DB[:table].first("id > ?", 4){id < 6} # SELECT * FROM table WHERE ((id > 4) AND (id < 6)) LIMIT 1
# => {:id=>5}

DB[:table].first(2){id < 2} # SELECT * FROM table WHERE (id < 2) LIMIT 2
# => [{:id=>1}]
# File lib/sequel/dataset/actions.rb, line 198
def first(*args, &block)
  case args.length
  when 0
    unless block
      return single_record
    end
  when 1
    arg = args[0]
    if arg.is_a?(Integer)
      res = if block
        if loader = cached_placeholder_literalizer(:_first_integer_cond_loader) do |pl|
            where(pl.arg).limit(pl.arg)
          end

          loader.all(filter_expr(&block), arg)
        else
          where(&block).limit(arg).all
        end
      else
        if loader = cached_placeholder_literalizer(:_first_integer_loader) do |pl|
           limit(pl.arg)
          end

          loader.all(arg)
        else
          limit(arg).all
        end
      end

      return res
    end
    args = arg
  end

  if loader = cached_placeholder_literalizer(:_first_cond_loader) do |pl|
      _single_record_ds.where(pl.arg)
    end

    loader.first(filter_expr(args, &block))
  else
    _single_record_ds.where(args, &block).single_record!
  end
end
first!(*args, &block) click to toggle source

Calls first. If first returns nil (signaling that no row matches), raise a Sequel::NoMatchingRow exception.

# File lib/sequel/dataset/actions.rb, line 244
def first!(*args, &block)
  first(*args, &block) || raise(Sequel::NoMatchingRow.new(self))
end
get(column=(no_arg=true; nil), &block) click to toggle source

Return the column value for the first matching record in the dataset. Raises an error if both an argument and block is given.

DB[:table].get(:id) # SELECT id FROM table LIMIT 1
# => 3

ds.get{sum(id)} # SELECT sum(id) AS v FROM table LIMIT 1
# => 6

You can pass an array of arguments to return multiple arguments, but you must make sure each element in the array has an alias that Sequel can determine:

DB[:table].get([:id, :name]) # SELECT id, name FROM table LIMIT 1
# => [3, 'foo']

DB[:table].get{[sum(id).as(sum), name]} # SELECT sum(id) AS sum, name FROM table LIMIT 1
# => [6, 'foo']
# File lib/sequel/dataset/actions.rb, line 266
def get(column=(no_arg=true; nil), &block)
  ds = naked
  if block
    raise(Error, ARG_BLOCK_ERROR_MSG) unless no_arg
    ds = ds.select(&block)
    column = ds.opts[:select]
    column = nil if column.is_a?(Array) && column.length < 2
  else
    case column
    when Array
      ds = ds.select(*column)
    when LiteralString, Symbol, SQL::Identifier, SQL::QualifiedIdentifier, SQL::AliasedExpression
      if loader = cached_placeholder_literalizer(:_get_loader) do |pl|
          ds.single_value_ds.select(pl.arg)
        end

        return loader.get(column)
      end

      ds = ds.select(column)
    else
      if loader = cached_placeholder_literalizer(:_get_alias_loader) do |pl|
          ds.single_value_ds.select(Sequel.as(pl.arg, :v))
        end

        return loader.get(column)
      end

      ds = ds.select(Sequel.as(column, :v))
    end
  end

  if column.is_a?(Array)
   if r = ds.single_record
     r.values_at(*hash_key_symbols(column))
   end
  else
    ds.single_value
  end
end
import(columns, values, opts=OPTS) click to toggle source

Inserts multiple records into the associated table. This method can be used to efficiently insert a large number of records into a table in a single query if the database supports it. Inserts are automatically wrapped in a transaction.

This method is called with a columns array and an array of value arrays:

DB[:table].import([:x, :y], [[1, 2], [3, 4]])
# INSERT INTO table (x, y) VALUES (1, 2) 
# INSERT INTO table (x, y) VALUES (3, 4)

This method also accepts a dataset instead of an array of value arrays:

DB[:table].import([:x, :y], DB[:table2].select(:a, :b))
# INSERT INTO table (x, y) SELECT a, b FROM table2

Options:

:commit_every

Open a new transaction for every given number of records. For example, if you provide a value of 50, will commit after every 50 records.

:return

When this is set to :primary_key, returns an array of autoincremented primary key values for the rows inserted.

:server

Set the server/shard to use for the transaction and insert queries.

:slice

Same as :commit_every, :commit_every takes precedence.

# File lib/sequel/dataset/actions.rb, line 332
def import(columns, values, opts=OPTS)
  return @db.transaction{insert(columns, values)} if values.is_a?(Dataset)

  return if values.empty?
  raise(Error, IMPORT_ERROR_MSG) if columns.empty?
  ds = opts[:server] ? server(opts[:server]) : self
  
  if slice_size = opts.fetch(:commit_every, opts.fetch(:slice, default_import_slice))
    offset = 0
    rows = []
    while offset < values.length
      rows << ds._import(columns, values[offset, slice_size], opts)
      offset += slice_size
    end
    rows.flatten
  else
    ds._import(columns, values, opts)
  end
end
insert(*values, &block) click to toggle source

Inserts values into the associated table. The returned value is generally the value of the primary key for the inserted row, but that is adapter dependent.

insert handles a number of different argument formats:

no arguments or single empty hash

Uses DEFAULT VALUES

single hash

Most common format, treats keys as columns and values as values

single array

Treats entries as values, with no columns

two arrays

Treats first array as columns, second array as values

single Dataset

Treats as an insert based on a selection from the dataset given, with no columns

array and dataset

Treats as an insert based on a selection from the dataset given, with the columns given by the array.

Examples:

DB[:items].insert
# INSERT INTO items DEFAULT VALUES

DB[:items].insert({})
# INSERT INTO items DEFAULT VALUES

DB[:items].insert([1,2,3])
# INSERT INTO items VALUES (1, 2, 3)

DB[:items].insert([:a, :b], [1,2])
# INSERT INTO items (a, b) VALUES (1, 2)

DB[:items].insert(:a => 1, :b => 2)
# INSERT INTO items (a, b) VALUES (1, 2)

DB[:items].insert(DB[:old_items])
# INSERT INTO items SELECT * FROM old_items

DB[:items].insert([:a, :b], DB[:old_items])
# INSERT INTO items (a, b) SELECT * FROM old_items
# File lib/sequel/dataset/actions.rb, line 387
def insert(*values, &block)
  sql = insert_sql(*values)
  if uses_returning?(:insert)
    returning_fetch_rows(sql, &block)
  else
    execute_insert(sql)
  end
end
interval(column=Sequel.virtual_row(&Proc.new)) click to toggle source

Returns the interval between minimum and maximum values for the given column/expression. Uses a virtual row block if no argument is given.

DB[:table].interval(:id) # SELECT (max(id) - min(id)) FROM table LIMIT 1
# => 6
DB[:table].interval{function(column)} # SELECT (max(function(column)) - min(function(column))) FROM table LIMIT 1
# => 7
# File lib/sequel/dataset/actions.rb, line 403
def interval(column=Sequel.virtual_row(&Proc.new))
  if loader = cached_placeholder_literalizer(:_interval_loader) do |pl|
      arg = pl.arg
      aggregate_dataset.limit(1).select((SQL::Function.new(:max, arg) - SQL::Function.new(:min, arg)).as(:interval))
    end

    loader.get(column)
  else
    aggregate_dataset.get{(max(column) - min(column)).as(:interval)}
  end
end
last(*args, &block) click to toggle source

Reverses the order and then runs first with the given arguments and block. Note that this will not necessarily give you the last record in the dataset, unless you have an unambiguous order. If there is not currently an order for this dataset, raises an Error.

DB[:table].order(:id).last # SELECT * FROM table ORDER BY id DESC LIMIT 1
# => {:id=>10}

DB[:table].order(Sequel.desc(:id)).last(2) # SELECT * FROM table ORDER BY id ASC LIMIT 2
# => [{:id=>1}, {:id=>2}]
# File lib/sequel/dataset/actions.rb, line 425
def last(*args, &block)
  raise(Error, 'No order specified') unless @opts[:order]
  reverse.first(*args, &block)
end
map(column=nil, &block) click to toggle source

Maps column values for each record in the dataset (if a column name is given), or performs the stock mapping functionality of Enumerable otherwise. Raises an Error if both an argument and block are given.

DB[:table].map(:id) # SELECT * FROM table
# => [1, 2, 3, ...]

DB[:table].map{|r| r[:id] * 2} # SELECT * FROM table
# => [2, 4, 6, ...]

You can also provide an array of column names:

DB[:table].map([:id, :name]) # SELECT * FROM table
# => [[1, 'A'], [2, 'B'], [3, 'C'], ...]
Calls superclass method
# File lib/sequel/dataset/actions.rb, line 444
def map(column=nil, &block)
  if column
    raise(Error, ARG_BLOCK_ERROR_MSG) if block
    return naked.map(column) if row_proc
    if column.is_a?(Array)
      super(){|r| r.values_at(*column)}
    else
      super(){|r| r[column]}
    end
  else
    super(&block)
  end
end
max(arg=Sequel.virtual_row(&Proc.new)) click to toggle source

Returns the maximum value for the given column/expression. Uses a virtual row block if no argument is given.

DB[:table].max(:id) # SELECT max(id) FROM table LIMIT 1
# => 10
DB[:table].max{function(column)} # SELECT max(function(column)) FROM table LIMIT 1
# => 7
# File lib/sequel/dataset/actions.rb, line 465
def max(arg=Sequel.virtual_row(&Proc.new))
  _aggregate(:max, arg)
end
min(arg=Sequel.virtual_row(&Proc.new)) click to toggle source

Returns the minimum value for the given column/expression. Uses a virtual row block if no argument is given.

DB[:table].min(:id) # SELECT min(id) FROM table LIMIT 1
# => 1
DB[:table].min{function(column)} # SELECT min(function(column)) FROM table LIMIT 1
# => 0
# File lib/sequel/dataset/actions.rb, line 476
def min(arg=Sequel.virtual_row(&Proc.new))
  _aggregate(:min, arg)
end
multi_insert(hashes, opts=OPTS) click to toggle source

This is a front end for import that allows you to submit an array of hashes instead of arrays of columns and values:

DB[:table].multi_insert([{:x => 1}, {:x => 2}])
# INSERT INTO table (x) VALUES (1)
# INSERT INTO table (x) VALUES (2)

Be aware that all hashes should have the same keys if you use this calling method, otherwise some columns could be missed or set to null instead of to default values.

This respects the same options as import.

# File lib/sequel/dataset/actions.rb, line 492
def multi_insert(hashes, opts=OPTS)
  return if hashes.empty?
  columns = hashes.first.keys
  import(columns, hashes.map{|h| columns.map{|c| h[c]}}, opts)
end
paged_each(opts=OPTS) { |row| ... } click to toggle source

Yields each row in the dataset, but interally uses multiple queries as needed to process the entire result set without keeping all rows in the dataset in memory, even if the underlying driver buffers all query results in memory.

Because this uses multiple queries internally, in order to remain consistent, it also uses a transaction internally. Additionally, to work correctly, the dataset must have unambiguous order. Using an ambiguous order can result in an infinite loop, as well as subtler bugs such as yielding duplicate rows or rows being skipped.

Sequel checks that the datasets using this method have an order, but it cannot ensure that the order is unambiguous.

Options:

:rows_per_fetch

The number of rows to fetch per query. Defaults to 1000.

:strategy

The strategy to use for paging of results. By default this is :offset, for using an approach with a limit and offset for every page. This can be set to :filter, which uses a limit and a filter that excludes rows from previous pages. In order for this strategy to work, you must be selecting the columns you are ordering by, and none of the columns can contain NULLs. Note that some Sequel adapters have optimized implementations that will use cursors or streaming regardless of the :strategy option used.

:filter_values

If the :strategy=>:filter option is used, this option should be a proc that accepts the last retreived row for the previous page and an array of ORDER BY expressions, and returns an array of values relating to those expressions for the last retrieved row. You will need to use this option if your ORDER BY expressions are not simple columns, if they contain qualified identifiers that would be ambiguous unqualified, if they contain any identifiers that are aliased in SELECT, and potentially other cases.

Examples:

DB[:table].order(:id).paged_each{|row| }
# SELECT * FROM table ORDER BY id LIMIT 1000
# SELECT * FROM table ORDER BY id LIMIT 1000 OFFSET 1000
# ...

DB[:table].order(:id).paged_each(:rows_per_fetch=>100){|row| }
# SELECT * FROM table ORDER BY id LIMIT 100
# SELECT * FROM table ORDER BY id LIMIT 100 OFFSET 100
# ...

DB[:table].order(:id).paged_each(:strategy=>:filter){|row| }
# SELECT * FROM table ORDER BY id LIMIT 1000
# SELECT * FROM table WHERE id > 1001 ORDER BY id LIMIT 1000
# ...

DB[:table].order(:table__id).paged_each(:strategy=>:filter,
  :filter_values=>proc{|row, exprs| [row[:id]]}){|row| }
# SELECT * FROM table ORDER BY id LIMIT 1000
# SELECT * FROM table WHERE id > 1001 ORDER BY id LIMIT 1000
# ...
# File lib/sequel/dataset/actions.rb, line 549
def paged_each(opts=OPTS)
  unless @opts[:order]
    raise Sequel::Error, "Dataset#paged_each requires the dataset be ordered"
  end
  unless block_given?
    return enum_for(:paged_each, opts)
  end

  total_limit = @opts[:limit]
  offset = @opts[:offset]
  if server = @opts[:server]
    opts = Hash[opts]
    opts[:server] = server
  end

  rows_per_fetch = opts[:rows_per_fetch] || 1000
  strategy = if offset || total_limit
    :offset
  else
    opts[:strategy] || :offset
  end

  db.transaction(opts) do
    case strategy
    when :filter
      filter_values = opts[:filter_values] || proc{|row, exprs| exprs.map{|e| row[hash_key_symbol(e)]}}
      base_ds = ds = limit(rows_per_fetch)
      while ds
        last_row = nil
        ds.each do |row|
          last_row = row
          yield row
        end
        ds = (base_ds.where(ignore_values_preceding(last_row, &filter_values)) if last_row)
      end
    else
      offset ||= 0
      num_rows_yielded = rows_per_fetch
      total_rows = 0

      while num_rows_yielded == rows_per_fetch && (total_limit.nil? || total_rows < total_limit)
        if total_limit && total_rows + rows_per_fetch > total_limit
          rows_per_fetch = total_limit - total_rows
        end

        num_rows_yielded = 0
        limit(rows_per_fetch, offset).each do |row|
          num_rows_yielded += 1
          total_rows += 1 if total_limit
          yield row
        end

        offset += rows_per_fetch
      end
    end
  end

  self
end
range(column=Sequel.virtual_row(&Proc.new)) click to toggle source

Returns a Range instance made from the minimum and maximum values for the given column/expression. Uses a virtual row block if no argument is given.

DB[:table].range(:id) # SELECT max(id) AS v1, min(id) AS v2 FROM table LIMIT 1
# => 1..10
DB[:table].interval{function(column)} # SELECT max(function(column)) AS v1, min(function(column)) AS v2 FROM table LIMIT 1
# => 0..7
# File lib/sequel/dataset/actions.rb, line 616
def range(column=Sequel.virtual_row(&Proc.new))
  r = if loader = cached_placeholder_literalizer(:_range_loader) do |pl|
        arg = pl.arg
        aggregate_dataset.limit(1).select(SQL::Function.new(:min, arg).as(:v1), SQL::Function.new(:max, arg).as(:v2))
      end

    loader.first(column)
  else
    aggregate_dataset.select{[min(column).as(v1), max(column).as(v2)]}.first
  end

  if r
    (r[:v1]..r[:v2])
  end
end
select_hash(key_column, value_column, opts = OPTS) click to toggle source

Returns a hash with key_column values as keys and value_column values as values. Similar to #to_hash, but only selects the columns given. Like #to_hash, it accepts an optional :hash parameter, into which entries will be merged.

DB[:table].select_hash(:id, :name) # SELECT id, name FROM table
# => {1=>'a', 2=>'b', ...}

You can also provide an array of column names for either the key_column, the value column, or both:

DB[:table].select_hash([:id, :foo], [:name, :bar]) # SELECT * FROM table
# {[1, 3]=>['a', 'c'], [2, 4]=>['b', 'd'], ...}

When using this method, you must be sure that each expression has an alias that Sequel can determine. Usually you can do this by calling the as method on the expression and providing an alias.

# File lib/sequel/dataset/actions.rb, line 649
def select_hash(key_column, value_column, opts = OPTS)
  _select_hash(:to_hash, key_column, value_column, opts)
end
select_hash_groups(key_column, value_column, opts = OPTS) click to toggle source

Returns a hash with key_column values as keys and an array of value_column values. Similar to #to_hash_groups, but only selects the columns given. Like #to_hash_groups, it accepts an optional :hash parameter, into which entries will be merged.

DB[:table].select_hash_groups(:name, :id) # SELECT id, name FROM table
# => {'a'=>[1, 4, ...], 'b'=>[2, ...], ...}

You can also provide an array of column names for either the key_column, the value column, or both:

DB[:table].select_hash_groups([:first, :middle], [:last, :id]) # SELECT * FROM table
# {['a', 'b']=>[['c', 1], ['d', 2], ...], ...}

When using this method, you must be sure that each expression has an alias that Sequel can determine. Usually you can do this by calling the as method on the expression and providing an alias.

# File lib/sequel/dataset/actions.rb, line 669
def select_hash_groups(key_column, value_column, opts = OPTS)
  _select_hash(:to_hash_groups, key_column, value_column, opts)
end
select_map(column=nil, &block) click to toggle source

Selects the column given (either as an argument or as a block), and returns an array of all values of that column in the dataset. If you give a block argument that returns an array with multiple entries, the contents of the resulting array are undefined. Raises an Error if called with both an argument and a block.

DB[:table].select_map(:id) # SELECT id FROM table
# => [3, 5, 8, 1, ...]

DB[:table].select_map{id * 2} # SELECT (id * 2) FROM table
# => [6, 10, 16, 2, ...]

You can also provide an array of column names:

DB[:table].select_map([:id, :name]) # SELECT id, name FROM table
# => [[1, 'A'], [2, 'B'], [3, 'C'], ...]

If you provide an array of expressions, you must be sure that each entry in the array has an alias that Sequel can determine. Usually you can do this by calling the as method on the expression and providing an alias.

# File lib/sequel/dataset/actions.rb, line 693
def select_map(column=nil, &block)
  _select_map(column, false, &block)
end
select_order_map(column=nil, &block) click to toggle source

The same as #select_map, but in addition orders the array by the column.

DB[:table].select_order_map(:id) # SELECT id FROM table ORDER BY id
# => [1, 2, 3, 4, ...]

DB[:table].select_order_map{id * 2} # SELECT (id * 2) FROM table ORDER BY (id * 2)
# => [2, 4, 6, 8, ...]

You can also provide an array of column names:

DB[:table].select_order_map([:id, :name]) # SELECT id, name FROM table ORDER BY id, name
# => [[1, 'A'], [2, 'B'], [3, 'C'], ...]

If you provide an array of expressions, you must be sure that each entry in the array has an alias that Sequel can determine. Usually you can do this by calling the as method on the expression and providing an alias.

# File lib/sequel/dataset/actions.rb, line 713
def select_order_map(column=nil, &block)
  _select_map(column, true, &block)
end
single_record() click to toggle source

Limits the dataset to one record, and returns the first record in the dataset, or nil if the dataset has no records. Users should probably use first instead of this method. Example:

DB[:test].single_record # SELECT * FROM test LIMIT 1
# => {:column_name=>'value'}
# File lib/sequel/dataset/actions.rb, line 723
def single_record
  _single_record_ds.single_record!
end
single_record!() click to toggle source

Returns the first record in dataset, without limiting the dataset. Returns nil if the dataset has no records. Users should probably use first instead of this method. This should only be used if you know the dataset is already limited to a single record. This method may be desirable to use for performance reasons, as it does not clone the receiver. Example:

DB[:test].single_record! # SELECT * FROM test
# => {:column_name=>'value'}
# File lib/sequel/dataset/actions.rb, line 735
def single_record!
  with_sql_first(select_sql)
end
single_value() click to toggle source

Returns the first value of the first record in the dataset. Returns nil if dataset is empty. Users should generally use get instead of this method. Example:

DB[:test].single_value # SELECT * FROM test LIMIT 1
# => 'value'
# File lib/sequel/dataset/actions.rb, line 745
def single_value
  single_value_ds.each do |r|
    r.each{|_, v| return v}
  end
  nil
end
single_value!() click to toggle source

Returns the first value of the first record in the dataset, without limiting the dataset. Returns nil if the dataset is empty. Users should generally use get instead of this method. Should not be used on graphed datasets or datasets that have row_procs that don't return hashes. This method may be desirable to use for performance reasons, as it does not clone the receiver.

DB[:test].single_value! # SELECT * FROM test
# => 'value'
# File lib/sequel/dataset/actions.rb, line 760
def single_value!
  with_sql_single_value(select_sql)
end
sum(arg=Sequel.virtual_row(&Proc.new)) click to toggle source

Returns the sum for the given column/expression. Uses a virtual row block if no column is given.

DB[:table].sum(:id) # SELECT sum(id) FROM table LIMIT 1
# => 55
DB[:table].sum{function(column)} # SELECT sum(function(column)) FROM table LIMIT 1
# => 10
# File lib/sequel/dataset/actions.rb, line 771
def sum(arg=Sequel.virtual_row(&Proc.new))
  _aggregate(:sum, arg)
end
to_hash(key_column, value_column = nil, opts = OPTS) click to toggle source

Returns a hash with one column used as key and another used as value. If rows have duplicate values for the key column, the latter row(s) will overwrite the value of the previous row(s). If the value_column is not given or nil, uses the entire hash as the value.

DB[:table].to_hash(:id, :name) # SELECT * FROM table
# {1=>'Jim', 2=>'Bob', ...}

DB[:table].to_hash(:id) # SELECT * FROM table
# {1=>{:id=>1, :name=>'Jim'}, 2=>{:id=>2, :name=>'Bob'}, ...}

You can also provide an array of column names for either the key_column, the value column, or both:

DB[:table].to_hash([:id, :foo], [:name, :bar]) # SELECT * FROM table
# {[1, 3]=>['Jim', 'bo'], [2, 4]=>['Bob', 'be'], ...}

DB[:table].to_hash([:id, :name]) # SELECT * FROM table
# {[1, 'Jim']=>{:id=>1, :name=>'Jim'}, [2, 'Bob'=>{:id=>2, :name=>'Bob'}, ...}

Options:

:all

Use all instead of each to retrieve the objects

:hash

The object into which the values will be placed. If this is not given, an empty hash is used. This can be used to use a hash with a default value or default proc.

# File lib/sequel/dataset/actions.rb, line 800
def to_hash(key_column, value_column = nil, opts = OPTS)
  h = opts[:hash] || {}
  meth = opts[:all] ? :all : :each
  if value_column
    return naked.to_hash(key_column, value_column, opts) if row_proc
    if value_column.is_a?(Array)
      if key_column.is_a?(Array)
        send(meth){|r| h[r.values_at(*key_column)] = r.values_at(*value_column)}
      else
        send(meth){|r| h[r[key_column]] = r.values_at(*value_column)}
      end
    else
      if key_column.is_a?(Array)
        send(meth){|r| h[r.values_at(*key_column)] = r[value_column]}
      else
        send(meth){|r| h[r[key_column]] = r[value_column]}
      end
    end
  elsif key_column.is_a?(Array)
    send(meth){|r| h[key_column.map{|k| r[k]}] = r}
  else
    send(meth){|r| h[r[key_column]] = r}
  end
  h
end
to_hash_groups(key_column, value_column = nil, opts = OPTS) click to toggle source

Returns a hash with one column used as key and the values being an array of column values. If the value_column is not given or nil, uses the entire hash as the value.

DB[:table].to_hash_groups(:name, :id) # SELECT * FROM table
# {'Jim'=>[1, 4, 16, ...], 'Bob'=>[2], ...}

DB[:table].to_hash_groups(:name) # SELECT * FROM table
# {'Jim'=>[{:id=>1, :name=>'Jim'}, {:id=>4, :name=>'Jim'}, ...], 'Bob'=>[{:id=>2, :name=>'Bob'}], ...}

You can also provide an array of column names for either the key_column, the value column, or both:

DB[:table].to_hash_groups([:first, :middle], [:last, :id]) # SELECT * FROM table
# {['Jim', 'Bob']=>[['Smith', 1], ['Jackson', 4], ...], ...}

DB[:table].to_hash_groups([:first, :middle]) # SELECT * FROM table
# {['Jim', 'Bob']=>[{:id=>1, :first=>'Jim', :middle=>'Bob', :last=>'Smith'}, ...], ...}

Options:

:all

Use all instead of each to retrieve the objects

:hash

The object into which the values will be placed. If this is not given, an empty hash is used. This can be used to use a hash with a default value or default proc.

to start with a new, empty hash.

# File lib/sequel/dataset/actions.rb, line 851
def to_hash_groups(key_column, value_column = nil, opts = OPTS)
  h = opts[:hash] || {}
  meth = opts[:all] ? :all : :each
  if value_column
    return naked.to_hash_groups(key_column, value_column, opts) if row_proc
    if value_column.is_a?(Array)
      if key_column.is_a?(Array)
        send(meth){|r| (h[r.values_at(*key_column)] ||= []) << r.values_at(*value_column)}
      else
        send(meth){|r| (h[r[key_column]] ||= []) << r.values_at(*value_column)}
      end
    else
      if key_column.is_a?(Array)
        send(meth){|r| (h[r.values_at(*key_column)] ||= []) << r[value_column]}
      else
        send(meth){|r| (h[r[key_column]] ||= []) << r[value_column]}
      end
    end
  elsif key_column.is_a?(Array)
    send(meth){|r| (h[key_column.map{|k| r[k]}] ||= []) << r}
  else
    send(meth){|r| (h[r[key_column]] ||= []) << r}
  end
  h
end
truncate() click to toggle source

Truncates the dataset. Returns nil.

DB[:table].truncate # TRUNCATE table
# => nil
# File lib/sequel/dataset/actions.rb, line 881
def truncate
  execute_ddl(truncate_sql)
end
update(values=OPTS, &block) click to toggle source

Updates values for the dataset. The returned value is generally the number of rows updated, but that is adapter dependent. values should a hash where the keys are columns to set and values are the values to which to set the columns.

DB[:table].update(:x=>nil) # UPDATE table SET x = NULL
# => 10

DB[:table].update(:x=>Sequel[:x]+1, :y=>0) # UPDATE table SET x = (x + 1), y = 0
# => 10
# File lib/sequel/dataset/actions.rb, line 895
def update(values=OPTS, &block)
  sql = update_sql(values)
  if uses_returning?(:update)
    returning_fetch_rows(sql, &block)
  else
    execute_dui(sql)
  end
end
with_sql_all(sql, &block) click to toggle source

Run the given SQL and return an array of all rows. If a block is given, each row is yielded to the block after all rows are loaded. See with_sql_each.

# File lib/sequel/dataset/actions.rb, line 906
def with_sql_all(sql, &block)
  _all(block){|a| with_sql_each(sql){|r| a << r}}
end
with_sql_delete(sql) click to toggle source

Execute the given SQL and return the number of rows deleted. This exists solely as an optimization, replacing with_sql(sql).delete. It's significantly faster as it does not require cloning the current dataset.

# File lib/sequel/dataset/actions.rb, line 913
def with_sql_delete(sql)
  execute_dui(sql)
end
Also aliased as: with_sql_update
with_sql_each(sql) { |call| ... } click to toggle source

Run the given SQL and yield each returned row to the block.

This method should not be called on a shared dataset if the columns selected in the given SQL do not match the columns in the receiver.

# File lib/sequel/dataset/actions.rb, line 922
def with_sql_each(sql)
  if rp = row_proc
    fetch_rows(sql){|r| yield rp.call(r)}
  else
    fetch_rows(sql){|r| yield r}
  end
  self
end
with_sql_first(sql) click to toggle source

Run the given SQL and return the first row, or nil if no rows were returned. See with_sql_each.

# File lib/sequel/dataset/actions.rb, line 933
def with_sql_first(sql)
  with_sql_each(sql){|r| return r}
  nil
end
with_sql_insert(sql) click to toggle source

Execute the given SQL and (on most databases) return the primary key of the inserted row.

# File lib/sequel/dataset/actions.rb, line 949
def with_sql_insert(sql)
  execute_insert(sql)
end
with_sql_single_value(sql) click to toggle source

Run the given SQL and return the first value in the first row, or nil if no rows were returned. For this to make sense, the SQL given should select only a single value. See with_sql_each.

# File lib/sequel/dataset/actions.rb, line 941
def with_sql_single_value(sql)
  if r = with_sql_first(sql)
    r.each{|_, v| return v}
  end
end
with_sql_update(sql)
Alias for: with_sql_delete

Protected Instance Methods

_import(columns, values, opts) click to toggle source

Internals of import. If primary key values are requested, use separate insert commands for each row. Otherwise, call multi_insert_sql and execute each statement it gives separately.

# File lib/sequel/dataset/actions.rb, line 958
def _import(columns, values, opts)
  trans_opts = Hash[opts].merge!(:server=>@opts[:server])
  if opts[:return] == :primary_key
    @db.transaction(trans_opts){values.map{|v| insert(columns, v)}}
  else
    stmts = multi_insert_sql(columns, values)
    @db.transaction(trans_opts){stmts.each{|st| execute_dui(st)}}
  end
end
_select_map_multiple(ret_cols) click to toggle source

Return an array of arrays of values given by the symbols in ret_cols.

# File lib/sequel/dataset/actions.rb, line 969
def _select_map_multiple(ret_cols)
  map{|r| r.values_at(*ret_cols)}
end
_select_map_single() click to toggle source

Returns an array of the first value in each row.

# File lib/sequel/dataset/actions.rb, line 974
def _select_map_single
  map{|r| r.values.first}
end
single_value_ds() click to toggle source

A dataset for returning single values from the current dataset.

# File lib/sequel/dataset/actions.rb, line 979
def single_value_ds
  clone(:limit=>1).ungraphed.naked
end

Private Instance Methods

_aggregate(function, arg) click to toggle source

Cached placeholder literalizer for methods that return values using aggregate functions.

# File lib/sequel/dataset/actions.rb, line 995
def _aggregate(function, arg)
  if loader = cached_placeholder_literalizer(:"_#{function}_loader") do |pl|
        aggregate_dataset.limit(1).select(SQL::Function.new(function, pl.arg).as(function))
      end
    loader.get(arg)
  else
    aggregate_dataset.get(SQL::Function.new(function, arg).as(function))
  end
end
_all(block) { |a| ... } click to toggle source

Internals of all and #with_sql_all

# File lib/sequel/dataset/actions.rb, line 986
def _all(block)
  a = []
  yield a
  post_load(a)
  a.each(&block) if block
  a
end
_hash_key_symbol(s, recursing=false) click to toggle source

Return a plain symbol given a potentially qualified or aliased symbol, specifying the symbol that is likely to be used as the hash key for the column when records are returned. Return nil if no hash key can be determined

# File lib/sequel/dataset/actions.rb, line 1087
def _hash_key_symbol(s, recursing=false)
  case s
  when Symbol
    _, c, a = split_symbol(s)
    (a || c).to_sym
  when SQL::Identifier, SQL::Wrapper
    _hash_key_symbol(s.value, true)
  when SQL::QualifiedIdentifier
    _hash_key_symbol(s.column, true)
  when SQL::AliasedExpression
    _hash_key_symbol(s.alias, true)
  when String
    s.to_sym if recursing
  end
end
_select_hash(meth, key_column, value_column, opts=OPTS) click to toggle source

Internals of select_hash and select_hash_groups

# File lib/sequel/dataset/actions.rb, line 1006
def _select_hash(meth, key_column, value_column, opts=OPTS)
  select(*(key_column.is_a?(Array) ? key_column : [key_column]) + (value_column.is_a?(Array) ? value_column : [value_column])).
    send(meth, hash_key_symbols(key_column), hash_key_symbols(value_column), opts)
end
_select_map(column, order, &block) click to toggle source

Internals of select_map and select_order_map

# File lib/sequel/dataset/actions.rb, line 1012
def _select_map(column, order, &block)
  ds = ungraphed.naked
  columns = Array(column)
  virtual_row_columns(columns, block)
  select_cols = order ? columns.map{|c| c.is_a?(SQL::OrderedExpression) ? c.expression : c} : columns
  ds = ds.order(*columns.map{|c| unaliased_identifier(c)}) if order
  if column.is_a?(Array) || (columns.length > 1)
    ds.select(*select_cols)._select_map_multiple(hash_key_symbols(select_cols))
  else
    ds.select(auto_alias_expression(select_cols.first))._select_map_single
  end
end
_single_record_ds() click to toggle source

A cached dataset for a single record for this dataset.

# File lib/sequel/dataset/actions.rb, line 1026
def _single_record_ds
  cached_dataset(:_single_record_ds){clone(:limit=>1)}
end
auto_alias_expression(v) click to toggle source

Automatically alias the given expression if it does not have an identifiable alias.

# File lib/sequel/dataset/actions.rb, line 1031
def auto_alias_expression(v)
  case v
  when LiteralString, Symbol, SQL::Identifier, SQL::QualifiedIdentifier, SQL::AliasedExpression
    v
  else
    SQL::AliasedExpression.new(v, :v)
  end
end
default_import_slice() click to toggle source

The default number of rows that can be inserted in a single INSERT statement via import. The default is for no limit.

# File lib/sequel/dataset/actions.rb, line 1042
def default_import_slice
  nil
end
default_server_opts(opts) click to toggle source

Set the server to use to :default unless it is already set in the passed opts

# File lib/sequel/dataset/actions.rb, line 1047
def default_server_opts(opts)
  if @db.sharded?
    opts = Hash[opts]
    opts[:server] = @opts[:server] || :default
  end
  opts
end
execute(sql, opts=OPTS, &block) click to toggle source

Execute the given select SQL on the database using execute. Use the :read_only server unless a specific server is set.

# File lib/sequel/dataset/actions.rb, line 1057
def execute(sql, opts=OPTS, &block)
  db = @db
  if db.sharded?
    opts = Hash[opts]
    opts[:server] = @opts[:server] || (@opts[:lock] ? :default : :read_only)
    opts
  end
  db.execute(sql, opts, &block)
end
execute_ddl(sql, opts=OPTS, &block) click to toggle source

Execute the given SQL on the database using execute_ddl.

# File lib/sequel/dataset/actions.rb, line 1068
def execute_ddl(sql, opts=OPTS, &block)
  @db.execute_ddl(sql, default_server_opts(opts), &block)
  nil
end
execute_dui(sql, opts=OPTS, &block) click to toggle source

Execute the given SQL on the database using execute_dui.

# File lib/sequel/dataset/actions.rb, line 1074
def execute_dui(sql, opts=OPTS, &block)
  @db.execute_dui(sql, default_server_opts(opts), &block)
end
execute_insert(sql, opts=OPTS, &block) click to toggle source

Execute the given SQL on the database using execute_insert.

# File lib/sequel/dataset/actions.rb, line 1079
def execute_insert(sql, opts=OPTS, &block)
  @db.execute_insert(sql, default_server_opts(opts), &block)
end
hash_key_symbol(s) click to toggle source

Return a plain symbol given a potentially qualified or aliased symbol, specifying the symbol that is likely to be used as the hash key for the column when records are returned. Raise Error if the hash key symbol cannot be returned.

# File lib/sequel/dataset/actions.rb, line 1107
def hash_key_symbol(s)
  if v = _hash_key_symbol(s)
    v
  else
    raise(Error, "#{s.inspect} is not supported, should be a Symbol, SQL::Identifier, SQL::QualifiedIdentifier, or SQL::AliasedExpression")
  end
end
hash_key_symbols(s) click to toggle source

If s is an array, return an array with the given hash key symbols. Otherwise, return a hash key symbol for the given expression If a hash key symbol cannot be determined, raise an error.

# File lib/sequel/dataset/actions.rb, line 1118
def hash_key_symbols(s)
  s.is_a?(Array) ? s.map{|c| hash_key_symbol(c)} : hash_key_symbol(s)
end
ignore_values_preceding(row) { |row, map(&:first)| ... } click to toggle source

Returns an expression that will ignore values preceding the given row, using the receiver's current order. This yields the row and the array of order expressions to the block, which should return an array of values to use.

# File lib/sequel/dataset/actions.rb, line 1125
def ignore_values_preceding(row)
  @opts[:order].map{|v| v.is_a?(SQL::OrderedExpression) ? v.expression : v}

  order_exprs = @opts[:order].map do |v|
    if v.is_a?(SQL::OrderedExpression)
      descending = v.descending
      v = v.expression
    else
      descending = false
    end
    [v, descending]
  end

  row_values = yield(row, order_exprs.map(&:first))

  last_expr = []
  cond = order_exprs.zip(row_values).map do |(v, descending), value|
    expr =  last_expr + [SQL::BooleanExpression.new(descending ? :< : :>, v, value)]
    last_expr += [SQL::BooleanExpression.new(:'=', v, value)]
    Sequel.&(*expr)
  end
  Sequel.|(*cond)
end
output_identifier(v) click to toggle source

Downcase identifiers by default when outputing them from the database.

# File lib/sequel/dataset/actions.rb, line 1150
def output_identifier(v)
  v = 'untitled' if v == ''
  v.to_s.downcase.to_sym
end
post_load(all_records) click to toggle source

This is run inside .all, after all of the records have been loaded via .each, but before any block passed to all is called. It is called with a single argument, an array of all returned records. Does nothing by default, added to make the model eager loading code simpler.

# File lib/sequel/dataset/actions.rb, line 1159
def post_load(all_records)
end
returning_fetch_rows(sql, &block) click to toggle source

Called by insert/update/delete when returning is used. Yields each row as a plain hash to the block if one is given, or returns an array of plain hashes for all rows if a block is not given

# File lib/sequel/dataset/actions.rb, line 1165
def returning_fetch_rows(sql, &block)
  if block
    default_server.fetch_rows(sql, &block)
    nil
  else
    rows = []
    default_server.fetch_rows(sql){|r| rows << r}
    rows
  end
end
unaliased_identifier(c) click to toggle source

Return the unaliased part of the identifier. Handles both implicit aliases in symbols, as well as SQL::AliasedExpression objects. Other objects are returned as is.

# File lib/sequel/dataset/actions.rb, line 1179
def unaliased_identifier(c)
  case c
  when Symbol
    table, column, aliaz = split_symbol(c)
    if aliaz
      table ? SQL::QualifiedIdentifier.new(table, column) : Sequel.identifier(column)
    else
      c
    end
  when SQL::AliasedExpression
    c.expression
  when SQL::OrderedExpression
    case expr = c.expression
    when Symbol, SQL::AliasedExpression
      SQL::OrderedExpression.new(unaliased_identifier(expr), c.descending, :nulls=>c.nulls)
    else
      c
    end
  else
    c
  end
end

3 - User Methods relating to SQL Creation

↑ top

Public Instance Methods

exists() click to toggle source

Returns an EXISTS clause for the dataset as an SQL::PlaceholderLiteralString.

DB.select(1).where(DB[:items].exists)
# SELECT 1 WHERE (EXISTS (SELECT * FROM items))
# File lib/sequel/dataset/sql.rb, line 13
def exists
  SQL::PlaceholderLiteralString.new(EXISTS, [self], true)
end
insert_sql(*values) click to toggle source

Returns an INSERT SQL query string. See insert.

DB[:items].insert_sql(:a=>1)
# => "INSERT INTO items (a) VALUES (1)"
# File lib/sequel/dataset/sql.rb, line 21
def insert_sql(*values)
  return static_sql(@opts[:sql]) if @opts[:sql]

  check_modification_allowed!

  columns = []

  case values.size
  when 0
    return insert_sql({})
  when 1
    case vals = values.at(0)
    when Hash
      values = []
      vals.each do |k,v| 
        columns << k
        values << v
      end
    when Dataset, Array, LiteralString
      values = vals
    end
  when 2
    if (v0 = values.at(0)).is_a?(Array) && ((v1 = values.at(1)).is_a?(Array) || v1.is_a?(Dataset) || v1.is_a?(LiteralString))
      columns, values = v0, v1
      raise(Error, "Different number of values and columns given to insert_sql") if values.is_a?(Array) and columns.length != values.length
    end
  end

  if values.is_a?(Array) && values.empty? && !insert_supports_empty_values? 
    columns, values = insert_empty_columns_values
  end
  clone(:columns=>columns, :values=>values).send(:_insert_sql)
end
literal_append(sql, v) click to toggle source

Append a literal representation of a value to the given SQL string.

If an unsupported object is given, an Error is raised.

# File lib/sequel/dataset/sql.rb, line 58
def literal_append(sql, v)
  case v
  when Symbol
    if skip_symbol_cache?
      literal_symbol_append(sql, v)
    else 
      unless l = db.literal_symbol(v)
        l = String.new
        literal_symbol_append(l, v)
        db.literal_symbol_set(v, l)
      end
      sql << l
    end
  when String
    case v
    when LiteralString
      sql << v
    when SQL::Blob
      literal_blob_append(sql, v)
    else
      literal_string_append(sql, v)
    end
  when Integer
    sql << literal_integer(v)
  when Hash
    literal_hash_append(sql, v)
  when SQL::Expression
    literal_expression_append(sql, v)
  when Float
    sql << literal_float(v)
  when BigDecimal
    sql << literal_big_decimal(v)
  when NilClass
    sql << literal_nil
  when TrueClass
    sql << literal_true
  when FalseClass
    sql << literal_false
  when Array
    literal_array_append(sql, v)
  when Time
    v.is_a?(SQLTime) ? literal_sqltime_append(sql, v) : literal_time_append(sql, v)
  when DateTime
    literal_datetime_append(sql, v)
  when Date
    sql << literal_date(v)
  when Dataset
    literal_dataset_append(sql, v)
  else
    literal_other_append(sql, v)
  end
end
multi_insert_sql(columns, values) click to toggle source

Returns an array of insert statements for inserting multiple records. This method is used by multi_insert to format insert statements and expects a keys array and and an array of value arrays.

This method should be overridden by descendants if the support inserting multiple records in a single SQL statement.

# File lib/sequel/dataset/sql.rb, line 117
def multi_insert_sql(columns, values)
  case multi_insert_sql_strategy
  when :values
    sql = LiteralString.new('VALUES ')
    expression_list_append(sql, values.map{|r| Array(r)})
    [insert_sql(columns, sql)]
  when :union
    c = false
    sql = LiteralString.new
    u = UNION_ALL_SELECT
    f = empty_from_sql
    values.each do |v|
      if c
        sql << u
      else
        sql << SELECT << SPACE
        c = true
      end
      expression_list_append(sql, v)
      sql << f if f
    end
    [insert_sql(columns, sql)]
  else
    values.map{|r| insert_sql(columns, r)}
  end
end
sql() click to toggle source

Same as select_sql, not aliased directly to make subclassing simpler.

# File lib/sequel/dataset/sql.rb, line 145
def sql
  select_sql
end
truncate_sql() click to toggle source

Returns a TRUNCATE SQL query string. See truncate

DB[:items].truncate_sql # => 'TRUNCATE items'
# File lib/sequel/dataset/sql.rb, line 152
def truncate_sql
  if opts[:sql]
    static_sql(opts[:sql])
  else
    check_truncation_allowed!
    raise(InvalidOperation, "Can't truncate filtered datasets") if opts[:where] || opts[:having]
    t = String.new
    source_list_append(t, opts[:from])
    _truncate_sql(t)
  end
end
update_sql(values = OPTS) click to toggle source

Formats an UPDATE statement using the given values. See update.

DB[:items].update_sql(:price => 100, :category => 'software')
# => "UPDATE items SET price = 100, category = 'software'

Raises an Error if the dataset is grouped or includes more than one table.

# File lib/sequel/dataset/sql.rb, line 171
def update_sql(values = OPTS)
  return static_sql(opts[:sql]) if opts[:sql]
  check_modification_allowed!
  clone(:values=>values).send(:_update_sql)
end

4 - Methods that describe what the dataset supports

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Public Instance Methods

provides_accurate_rows_matched?() click to toggle source

Whether this dataset will provide accurate number of rows matched for delete and update statements. Accurate in this case is the number of rows matched by the dataset's filter.

# File lib/sequel/dataset/features.rb, line 18
def provides_accurate_rows_matched?
  true
end
quote_identifiers?() click to toggle source

Whether this dataset quotes identifiers.

# File lib/sequel/dataset/features.rb, line 11
def quote_identifiers?
  @opts.fetch(:quote_identifiers, true)
end
recursive_cte_requires_column_aliases?() click to toggle source

Whether you must use a column alias list for recursive CTEs (false by default).

# File lib/sequel/dataset/features.rb, line 24
def recursive_cte_requires_column_aliases?
  false
end
requires_placeholder_type_specifiers?() click to toggle source

Whether type specifiers are required for prepared statement/bound variable argument placeholders (i.e. :bv__integer)

# File lib/sequel/dataset/features.rb, line 36
def requires_placeholder_type_specifiers?
  false
end
requires_sql_standard_datetimes?() click to toggle source

Whether the dataset requires SQL standard datetimes (false by default, as most allow strings with ISO 8601 format).

# File lib/sequel/dataset/features.rb, line 30
def requires_sql_standard_datetimes?
  false
end
supports_cte?(type=:select) click to toggle source

Whether the dataset supports common table expressions (the WITH clause). If given, type can be :select, :insert, :update, or :delete, in which case it determines whether WITH is supported for the respective statement type.

# File lib/sequel/dataset/features.rb, line 43
def supports_cte?(type=:select)
  false
end
supports_cte_in_subqueries?() click to toggle source

Whether the dataset supports common table expressions (the WITH clause) in subqueries. If false, applies the WITH clause to the main query, which can cause issues if multiple WITH clauses use the same name.

# File lib/sequel/dataset/features.rb, line 50
def supports_cte_in_subqueries?
  false
end
supports_derived_column_lists?() click to toggle source

Whether the database supports derived column lists (e.g. “table_expr AS table_alias(column_alias1, column_alias2, …)”), true by default.

# File lib/sequel/dataset/features.rb, line 57
def supports_derived_column_lists?
  true
end
supports_distinct_on?() click to toggle source

Whether the dataset supports or can emulate the DISTINCT ON clause, false by default.

# File lib/sequel/dataset/features.rb, line 62
def supports_distinct_on?
  false
end
supports_group_cube?() click to toggle source

Whether the dataset supports CUBE with GROUP BY.

# File lib/sequel/dataset/features.rb, line 67
def supports_group_cube?
  false
end
supports_group_rollup?() click to toggle source

Whether the dataset supports ROLLUP with GROUP BY.

# File lib/sequel/dataset/features.rb, line 72
def supports_group_rollup?
  false
end
supports_grouping_sets?() click to toggle source

Whether the dataset supports GROUPING SETS with GROUP BY.

# File lib/sequel/dataset/features.rb, line 77
def supports_grouping_sets?
  false
end
supports_insert_select?() click to toggle source

Whether this dataset supports the insert_select method for returning all columns values directly from an insert query.

# File lib/sequel/dataset/features.rb, line 83
def supports_insert_select?
  supports_returning?(:insert)
end
supports_intersect_except?() click to toggle source

Whether the dataset supports the INTERSECT and EXCEPT compound operations, true by default.

# File lib/sequel/dataset/features.rb, line 88
def supports_intersect_except?
  true
end
supports_intersect_except_all?() click to toggle source

Whether the dataset supports the INTERSECT ALL and EXCEPT ALL compound operations, true by default.

# File lib/sequel/dataset/features.rb, line 93
def supports_intersect_except_all?
  true
end
supports_is_true?() click to toggle source

Whether the dataset supports the IS TRUE syntax.

# File lib/sequel/dataset/features.rb, line 98
def supports_is_true?
  true
end
supports_join_using?() click to toggle source

Whether the dataset supports the JOIN table USING (column1, …) syntax.

# File lib/sequel/dataset/features.rb, line 103
def supports_join_using?
  true
end
supports_lateral_subqueries?() click to toggle source

Whether the dataset supports LATERAL for subqueries in the FROM or JOIN clauses.

# File lib/sequel/dataset/features.rb, line 108
def supports_lateral_subqueries?
  false
end
supports_limits_in_correlated_subqueries?() click to toggle source

Whether limits are supported in correlated subqueries. True by default.

# File lib/sequel/dataset/features.rb, line 113
def supports_limits_in_correlated_subqueries?
  true
end
supports_modifying_joins?() click to toggle source

Whether modifying joined datasets is supported.

# File lib/sequel/dataset/features.rb, line 118
def supports_modifying_joins?
  false
end
supports_multiple_column_in?() click to toggle source

Whether the IN/NOT IN operators support multiple columns when an array of values is given.

# File lib/sequel/dataset/features.rb, line 124
def supports_multiple_column_in?
  true
end
supports_offsets_in_correlated_subqueries?() click to toggle source

Whether offsets are supported in correlated subqueries, true by default.

# File lib/sequel/dataset/features.rb, line 129
def supports_offsets_in_correlated_subqueries?
  true
end
supports_ordered_distinct_on?() click to toggle source

Whether the dataset supports or can fully emulate the DISTINCT ON clause, including respecting the ORDER BY clause, false by default

# File lib/sequel/dataset/features.rb, line 135
def supports_ordered_distinct_on?
  supports_distinct_on?
end
supports_regexp?() click to toggle source

Whether the dataset supports pattern matching by regular expressions.

# File lib/sequel/dataset/features.rb, line 140
def supports_regexp?
  false
end
supports_replace?() click to toggle source

Whether the dataset supports REPLACE syntax, false by default.

# File lib/sequel/dataset/features.rb, line 145
def supports_replace?
  false
end
supports_returning?(type) click to toggle source

Whether the RETURNING clause is supported for the given type of query. type can be :insert, :update, or :delete.

# File lib/sequel/dataset/features.rb, line 151
def supports_returning?(type)
  false
end
supports_select_all_and_column?() click to toggle source

Whether the database supports SELECT *, column FROM table

# File lib/sequel/dataset/features.rb, line 161
def supports_select_all_and_column?
  true
end
supports_skip_locked?() click to toggle source

Whether the dataset supports skipping locked rows when returning data.

# File lib/sequel/dataset/features.rb, line 156
def supports_skip_locked?
  false
end
supports_timestamp_timezones?() click to toggle source

Whether the dataset supports timezones in literal timestamps

# File lib/sequel/dataset/features.rb, line 166
def supports_timestamp_timezones?
  false
end
supports_timestamp_usecs?() click to toggle source

Whether the dataset supports fractional seconds in literal timestamps

# File lib/sequel/dataset/features.rb, line 171
def supports_timestamp_usecs?
  true
end
supports_where_true?() click to toggle source

Whether the dataset supports WHERE TRUE (or WHERE 1 for databases that that use 1 for true).

# File lib/sequel/dataset/features.rb, line 182
def supports_where_true?
  true
end
supports_window_functions?() click to toggle source

Whether the dataset supports window functions.

# File lib/sequel/dataset/features.rb, line 176
def supports_window_functions?
  false
end

Private Instance Methods

insert_supports_empty_values?() click to toggle source

Whether insert(nil) or insert({}) must be emulated by using at least one value, false by default.

# File lib/sequel/dataset/features.rb, line 190
def insert_supports_empty_values?
  true
end
supports_quoted_function_names?() click to toggle source

Whether the database supports quoting function names, false by default.

# File lib/sequel/dataset/features.rb, line 195
def supports_quoted_function_names?
  false
end
uses_returning?(type) click to toggle source

Whether the RETURNING clause is used for the given dataset. type can be :insert, :update, or :delete.

# File lib/sequel/dataset/features.rb, line 201
def uses_returning?(type)
  opts[:returning] && !@opts[:sql] && supports_returning?(type)
end
uses_with_rollup?() click to toggle source

Whether the dataset uses WITH ROLLUP/CUBE instead of ROLLUP()/CUBE().

# File lib/sequel/dataset/features.rb, line 206
def uses_with_rollup?
  false
end

5 - Methods related to dataset graphing

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Public Instance Methods

add_graph_aliases(graph_aliases) click to toggle source

Adds the given graph aliases to the list of graph aliases to use, unlike set_graph_aliases, which replaces the list (the equivalent of select_append when graphing). See set_graph_aliases.

DB[:table].add_graph_aliases(:some_alias=>[:table, :column])
# SELECT ..., table.column AS some_alias
# File lib/sequel/dataset/graph.rb, line 17
def add_graph_aliases(graph_aliases)
  unless (ga = opts[:graph_aliases]) || (opts[:graph] && (ga = opts[:graph][:column_aliases]))
    raise Error, "cannot call add_graph_aliases on a dataset that has not been called with graph or set_graph_aliases"
  end
  columns, graph_aliases = graph_alias_columns(graph_aliases)
  select_append(*columns).clone(:graph_aliases => Hash[ga].merge!(graph_aliases).freeze)
end
graph(dataset, join_conditions = nil, options = OPTS, &block) click to toggle source

Similar to Dataset#join_table, but uses unambiguous aliases for selected columns and keeps metadata about the aliases for use in other methods.

Arguments:

dataset

Can be a symbol (specifying a table), another dataset, or an SQL::Identifier, SQL::QualifiedIdentifier, or SQL::AliasedExpression.

join_conditions

Any condition(s) allowed by join_table.

block

A block that is passed to join_table.

Options:

:from_self_alias

The alias to use when the receiver is not a graphed dataset but it contains multiple FROM tables or a JOIN. In this case, the receiver is wrapped in a from_self before graphing, and this option determines the alias to use.

:implicit_qualifier

The qualifier of implicit conditions, see join_table.

:join_only

Only join the tables, do not change the selected columns.

:join_type

The type of join to use (passed to join_table). Defaults to :left_outer.

:qualify

The type of qualification to do, see join_table.

:select

An array of columns to select. When not used, selects all columns in the given dataset. When set to false, selects no columns and is like simply joining the tables, though graph keeps some metadata about the join that makes it important to use graph instead of join_table.

:table_alias

The alias to use for the table. If not specified, doesn't alias the table. You will get an error if the alias (or table) name is used more than once.

# File lib/sequel/dataset/graph.rb, line 51
def graph(dataset, join_conditions = nil, options = OPTS, &block)
  # Allow the use of a dataset or symbol as the first argument
  # Find the table name/dataset based on the argument
  table_alias = options[:table_alias]
  table = dataset
  create_dataset = true

  case dataset
  when Symbol
    # let alias be the same as the table name (sans any optional schema)
    # unless alias explicitly given in the symbol using ___ notation
    table_alias ||= split_symbol(table).compact.last
  when Dataset
    if dataset.simple_select_all?
      table = dataset.opts[:from].first
      table_alias ||= table
    else
      table_alias ||= dataset_alias((@opts[:num_dataset_sources] || 0)+1)
    end
    create_dataset = false
  when SQL::Identifier
    table_alias ||= table.value
  when SQL::QualifiedIdentifier
    table_alias ||= split_qualifiers(table).last
  when SQL::AliasedExpression
    return graph(table.expression, join_conditions, {:table_alias=>table.alias}.merge!(options), &block)
  else
    raise Error, "The dataset argument should be a symbol or dataset"
  end
  table_alias = table_alias.to_sym

  if create_dataset
    dataset = db.from(table)
  end

  # Raise Sequel::Error with explanation that the table alias has been used
  raise_alias_error = lambda do
    raise(Error, "this #{options[:table_alias] ? 'alias' : 'table'} has already been been used, please specify "            "#{options[:table_alias] ? 'a different alias' : 'an alias via the :table_alias option'}") 
  end

  # Only allow table aliases that haven't been used
  raise_alias_error.call if @opts[:graph] && @opts[:graph][:table_aliases] && @opts[:graph][:table_aliases].include?(table_alias)
  
  table_alias_qualifier = qualifier_from_alias_symbol(table_alias, table)
  implicit_qualifier = options[:implicit_qualifier]
  ds = self

  # Use a from_self if this is already a joined table (or from_self specifically disabled for graphs)
  if (@opts[:graph_from_self] != false && !@opts[:graph] && joined_dataset?)
    from_selfed = true
    implicit_qualifier = options[:from_self_alias] || first_source
    ds = ds.from_self(:alias=>implicit_qualifier)
  end
  
  # Join the table early in order to avoid cloning the dataset twice
  ds = ds.join_table(options[:join_type] || :left_outer, table, join_conditions, :table_alias=>table_alias_qualifier, :implicit_qualifier=>implicit_qualifier, :qualify=>options[:qualify], &block)

  return ds if options[:join_only]

  opts = ds.opts

  # Whether to include the table in the result set
  add_table = options[:select] == false ? false : true
  # Whether to add the columns to the list of column aliases
  add_columns = !ds.opts.include?(:graph_aliases)

  if graph = opts[:graph]
    graph = graph.dup
    select = opts[:select].dup
    [:column_aliases, :table_aliases, :column_alias_num].each{|k| graph[k] = graph[k].dup}
  else
    # Setup the initial graph data structure if it doesn't exist
    qualifier = ds.first_source_alias
    master = alias_symbol(qualifier)
    raise_alias_error.call if master == table_alias

    # Master hash storing all .graph related information
    graph = {}

    # Associates column aliases back to tables and columns
    column_aliases = graph[:column_aliases] = {}

    # Associates table alias (the master is never aliased)
    table_aliases = graph[:table_aliases] = {master=>self}

    # Keep track of the alias numbers used
    ca_num = graph[:column_alias_num] = Hash.new(0)

    # All columns in the master table are never
    # aliased, but are not included if set_graph_aliases
    # has been used.
    if add_columns
      if (select = @opts[:select]) && !select.empty? && !(select.length == 1 && (select.first.is_a?(SQL::ColumnAll)))
        select = select.map do |sel|
          raise Error, "can't figure out alias to use for graphing for #{sel.inspect}" unless column = _hash_key_symbol(sel)
          column_aliases[column] = [master, column]
          if from_selfed
            # Initial dataset was wrapped in subselect, selected all
            # columns in the subselect, qualified by the subselect alias.
            Sequel.qualify(qualifier, Sequel.identifier(column))
          else
            # Initial dataset not wrapped in subslect, just make
            # sure columns are qualified in some way.
            qualified_expression(sel, qualifier)
          end
        end
      else
        select = columns.map do |column|
          column_aliases[column] = [master, column]
          SQL::QualifiedIdentifier.new(qualifier, column)
        end
      end
    end
  end

  # Add the table alias to the list of aliases
  # Even if it isn't been used in the result set,
  # we add a key for it with a nil value so we can check if it
  # is used more than once
  table_aliases = graph[:table_aliases]
  table_aliases[table_alias] = add_table ? dataset : nil

  # Add the columns to the selection unless we are ignoring them
  if add_table && add_columns
    column_aliases = graph[:column_aliases]
    ca_num = graph[:column_alias_num]
    # Which columns to add to the result set
    cols = options[:select] || dataset.columns
    # If the column hasn't been used yet, don't alias it.
    # If it has been used, try table_column.
    # If that has been used, try table_column_N 
    # using the next value of N that we know hasn't been
    # used
    cols.each do |column|
      col_alias, identifier = if column_aliases[column]
        column_alias = :"#{table_alias}_#{column}"
        if column_aliases[column_alias]
          column_alias_num = ca_num[column_alias]
          column_alias = :"#{column_alias}_#{column_alias_num}" 
          ca_num[column_alias] += 1
        end
        [column_alias, SQL::AliasedExpression.new(SQL::QualifiedIdentifier.new(table_alias_qualifier, column), column_alias)]
      else
        ident = SQL::QualifiedIdentifier.new(table_alias_qualifier, column)
        [column, ident]
      end
      column_aliases[col_alias] = [table_alias, column].freeze
      select.push(identifier)
    end
  end
  [:column_aliases, :table_aliases, :column_alias_num].each{|k| graph[k].freeze}
  ds = ds.clone(:graph=>graph.freeze)
  add_columns ? ds.select(*select) : ds
end
set_graph_aliases(graph_aliases) click to toggle source

This allows you to manually specify the graph aliases to use when using graph. You can use it to only select certain columns, and have those columns mapped to specific aliases in the result set. This is the equivalent of select for a graphed dataset, and must be used instead of select whenever graphing is used.

graph_aliases

Should be a hash with keys being symbols of column aliases, and values being either symbols or arrays with one to three elements. If the value is a symbol, it is assumed to be the same as a one element array containing that symbol. The first element of the array should be the table alias symbol. The second should be the actual column name symbol. If the array only has a single element the column name symbol will be assumed to be the same as the corresponding hash key. If the array has a third element, it is used as the value returned, instead of table_alias.column_name.

DB[:artists].graph(:albums, :artist_id=>:id).
  set_graph_aliases(:name=>:artists,
                    :album_name=>[:albums, :name],
                    :forty_two=>[:albums, :fourtwo, 42]).first
# SELECT artists.name, albums.name AS album_name, 42 AS forty_two ...
# File lib/sequel/dataset/graph.rb, line 230
def set_graph_aliases(graph_aliases)
  columns, graph_aliases = graph_alias_columns(graph_aliases)
  select(*columns).clone(:graph_aliases=>graph_aliases.freeze)
end
ungraphed() click to toggle source

Remove the splitting of results into subhashes, and all metadata related to the current graph (if any).

# File lib/sequel/dataset/graph.rb, line 237
def ungraphed
  clone(:graph=>nil, :graph_aliases=>nil)
end

Private Instance Methods

graph_alias_columns(graph_aliases) click to toggle source

Transform the hash of graph aliases and return a two element array where the first element is an array of identifiers suitable to pass to a select method, and the second is a new hash of preprocessed graph aliases.

# File lib/sequel/dataset/graph.rb, line 265
def graph_alias_columns(graph_aliases)
  gas = {}
  identifiers = graph_aliases.collect do |col_alias, tc| 
    table, column, value = Array(tc)
    column ||= col_alias
    gas[col_alias] = [table, column].freeze
    identifier = value || SQL::QualifiedIdentifier.new(table, column)
    identifier = SQL::AliasedExpression.new(identifier, col_alias) if value || column != col_alias
    identifier
  end
  [identifiers, gas]
end
qualifier_from_alias_symbol(aliaz, identifier) click to toggle source

Wrap the alias symbol in an SQL::Identifier if the identifier on which is based is an SQL::Identifier. This works around cases where the alias symbol contains double embedded underscores which would be considered an implicit qualified identifier if not wrapped in an SQL::Identifier.

# File lib/sequel/dataset/graph.rb, line 247
def qualifier_from_alias_symbol(aliaz, identifier)
  case identifier
  when SQL::QualifiedIdentifier
    if identifier.column.is_a?(String)
      Sequel.identifier(aliaz)
    else
      aliaz
    end
  when SQL::Identifier
    Sequel.identifier(aliaz)
  else
    aliaz
  end
end

6 - Miscellaneous methods

↑ top

Constants

ARG_BLOCK_ERROR_MSG
ARRAY_ACCESS_ERROR_MSG
IMPORT_ERROR_MSG
NOTIMPL_MSG

Attributes

db[R]

The database related to this dataset. This is the Database instance that will execute all of this dataset's queries.

opts[R]

The hash of options for this dataset, keys are symbols.

Public Class Methods

new(db) click to toggle source

Constructs a new Dataset instance with an associated database and options. Datasets are usually constructed by invoking the Sequel::Database#[] method:

DB[:posts]

Sequel::Dataset is an abstract class that is not useful by itself. Each database adapter provides a subclass of Sequel::Dataset, and has the Sequel::Database#dataset method return an instance of that subclass.

# File lib/sequel/dataset/misc.rb, line 29
def initialize(db)
  @db = db
  @opts = {}
  @cache = {}
end

Public Instance Methods

==(o) click to toggle source

Define a hash value such that datasets with the same class, DB, and opts will be considered equal.

# File lib/sequel/dataset/misc.rb, line 37
def ==(o)
  o.is_a?(self.class) && db == o.db && opts == o.opts
end
current_datetime() click to toggle source

An object representing the current date or time, should be an instance of Sequel.datetime_class.

# File lib/sequel/dataset/misc.rb, line 43
def current_datetime
  Sequel.datetime_class.now
end
dup() click to toggle source

Similar to clone, but returns an unfrozen clone if the receiver is frozen.

# File lib/sequel/dataset/misc.rb, line 54
def dup
  _clone(:freeze=>false)
end
each_server() { |server(s)| ... } click to toggle source

Yield a dataset for each server in the connection pool that is tied to that server. Intended for use in sharded environments where all servers need to be modified with the same data:

DB[:configs].where(:key=>'setting').each_server{|ds| ds.update(:value=>'new_value')}
# File lib/sequel/dataset/misc.rb, line 72
def each_server
  db.servers.each{|s| yield server(s)}
end
eql?(o) click to toggle source

Alias for ==

# File lib/sequel/dataset/misc.rb, line 48
def eql?(o)
  self == o
end
escape_like(string) click to toggle source

Returns the string with the LIKE metacharacters (% and _) escaped. Useful for when the LIKE term is a user-provided string where metacharacters should not be recognized. Example:

ds.escape_like("foo\\%_") # 'foo\\\%\_'
# File lib/sequel/dataset/misc.rb, line 81
def escape_like(string)
  string.gsub(/[\%_]/){|m| "\\#{m}"}
end
freeze() click to toggle source

Freeze the opts when freezing the dataset.

Calls superclass method
# File lib/sequel/dataset/misc.rb, line 87
def freeze
  @opts.freeze
  super
end

7 - Mutation methods

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Constants

MUTATION_METHODS

All methods that should have a ! method added that modifies the receiver.

Public Class Methods

def_mutation_method(*meths) click to toggle source

Setup mutation (e.g. filter!) methods. These operate the same as the non-! methods, but replace the options of the current dataset with the options of the resulting dataset.

Do not call this method with untrusted input, as that can result in arbitrary code execution.

# File lib/sequel/dataset/mutation.rb, line 18
def self.def_mutation_method(*meths)
  options = meths.pop if meths.last.is_a?(Hash)
  mod = options[:module] if options
  mod ||= self
  meths.each do |meth|
    mod.class_eval("def #{meth}!(*args, &block); mutation_method(:#{meth}, *args, &block) end", __FILE__, __LINE__)
  end
end

Public Instance Methods

extension!(*exts) click to toggle source

Like extension, but modifies and returns the receiver instead of returning a modified clone.

# File lib/sequel/dataset/mutation.rb, line 31
def extension!(*exts)
  raise_if_frozen!
  _extension!(exts)
end
from_self!(*args, &block) click to toggle source

Avoid self-referential dataset by cloning.

# File lib/sequel/dataset/mutation.rb, line 37
def from_self!(*args, &block)
  raise_if_frozen!
  @opts = clone.from_self(*args, &block).opts
  self
end
naked!() click to toggle source

Remove the row_proc from the current dataset.

# File lib/sequel/dataset/mutation.rb, line 44
def naked!
  raise_if_frozen!
  @opts[:row_proc] = nil
  self
end
quote_identifiers=(v) click to toggle source

Set whether to quote identifiers for this dataset

# File lib/sequel/dataset/mutation.rb, line 51
def quote_identifiers=(v)
  raise_if_frozen!
  skip_symbol_cache!
  @opts[:quote_identifiers] = v
end
row_proc=(v) click to toggle source

Override the row_proc for this dataset

# File lib/sequel/dataset/mutation.rb, line 58
def row_proc=(v)
  raise_if_frozen!
  @opts[:row_proc] = v
end

Private Instance Methods

_extension!(exts) click to toggle source

Load the extensions into the receiver, without checking if the receiver is frozen.

# File lib/sequel/dataset/mutation.rb, line 66
def _extension!(exts)
  Sequel.extension(*exts)
  exts.each do |ext|
    if pr = Sequel.synchronize{EXTENSIONS[ext]}
      pr.call(self)
    else
      raise(Error, "Extension #{ext} does not have specific support handling individual datasets (try: Sequel.extension #{ext.inspect})")
    end
  end
  self
end
mutation_method(meth, *args, &block) click to toggle source

Modify the receiver with the results of sending the meth, args, and block to the receiver and merging the options of the resulting dataset into the receiver's options.

# File lib/sequel/dataset/mutation.rb, line 81
def mutation_method(meth, *args, &block)
  raise_if_frozen!
  @opts = send(meth, *args, &block).opts
  @cache = {}
  self
end
raise_if_frozen!() click to toggle source

Raise a RuntimeError if the receiver is frozen

# File lib/sequel/dataset/mutation.rb, line 89
def raise_if_frozen!
  if frozen?
    raise RuntimeError, "can't modify frozen #{visible_class_name}"
  end
end
skip_symbol_cache!() click to toggle source

Set the dataset to skip the symbol cache

# File lib/sequel/dataset/mutation.rb, line 96
def skip_symbol_cache!
  @opts[:skip_symbol_cache] = true
end

8 - Methods related to prepared statements or bound variables

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Constants

DEFAULT_PREPARED_STATEMENT_MODULE_METHODS
PREPARED_ARG_PLACEHOLDER
PREPARED_STATEMENT_MODULE_CODE

Public Class Methods

def_deprecated_opts_setter(mod, *meths) click to toggle source
# File lib/sequel/dataset/prepared_statements.rb, line 39
def self.def_deprecated_opts_setter(mod, *meths)
  meths.each do |meth|
    mod.send(:define_method, :"#{meth}=") do |v|
      # :nocov:
      Sequel::Deprecation.deprecate("Dataset##{meth}=", "The API has changed, and this value should now be passed in as an option via Dataset#clone.")
      @opts[meth] = v
      # :nocov:
    end
  end
end

Private Class Methods

prepared_statements_module(code, mods, meths=DEFAULT_PREPARED_STATEMENT_MODULE_METHODS, &block) click to toggle source
# File lib/sequel/dataset/prepared_statements.rb, line 19
def self.prepared_statements_module(code, mods, meths=DEFAULT_PREPARED_STATEMENT_MODULE_METHODS, &block)
  code = PREPARED_STATEMENT_MODULE_CODE[code] || code

  Module.new do
    Array(mods).each do |mod|
      include mod
    end

    if block
      module_eval(&block)
    end

    meths.each do |meth|
      module_eval("def #{meth}(sql, opts=Sequel::OPTS) #{code}; super end", __FILE__, __LINE__)
    end
    private(*meths)
  end
end

Public Instance Methods

bind(bind_vars={}) click to toggle source

Set the bind variables to use for the call. If bind variables have already been set for this dataset, they are updated with the contents of bind_vars.

DB[:table].where(:id=>:$id).bind(:id=>1).call(:first)
# SELECT * FROM table WHERE id = ? LIMIT 1 -- (1)
# => {:id=>1}
# File lib/sequel/dataset/prepared_statements.rb, line 289
def bind(bind_vars={})
  bind_vars = if bv = @opts[:bind_vars]
    Hash[bv].merge!(bind_vars).freeze
  else
    if bind_vars.frozen?
      bind_vars
    else
      Hash[bind_vars]
    end
  end

  clone(:bind_vars=>bind_vars)
end
call(type, bind_variables={}, *values, &block) click to toggle source

For the given type (:select, :first, :insert, :insert_select, :update, or :delete), run the sql with the bind variables specified in the hash. values is a hash passed to insert or update (if one of those types is used), which may contain placeholders.

DB[:table].where(:id=>:$id).call(:first, :id=>1)
# SELECT * FROM table WHERE id = ? LIMIT 1 -- (1)
# => {:id=>1}
# File lib/sequel/dataset/prepared_statements.rb, line 310
def call(type, bind_variables={}, *values, &block)
  to_prepared_statement(type, values, :extend=>bound_variable_modules).call(bind_variables, &block)
end
prepare(type, name=nil, *values) click to toggle source

Prepare an SQL statement for later execution. Takes a type similar to call, and the name symbol of the prepared statement. While name defaults to nil, it should always be provided as a symbol for the name of the prepared statement, as some databases require that prepared statements have names.

This returns a clone of the dataset extended with PreparedStatementMethods, which you can call with the hash of bind variables to use. The prepared statement is also stored in the associated database, where it can be called by name. The following usage is identical:

ps = DB[:table].where(:name=>:$name).prepare(:first, :select_by_name)

ps.call(:name=>'Blah')
# SELECT * FROM table WHERE name = ? -- ('Blah')
# => {:id=>1, :name=>'Blah'}

DB.call(:select_by_name, :name=>'Blah') # Same thing
# File lib/sequel/dataset/prepared_statements.rb, line 332
def prepare(type, name=nil, *values)
  ps = to_prepared_statement(type, values, :name=>name, :extend=>prepared_statement_modules)

  if name
    ps.prepared_sql
    db.set_prepared_statement(name, ps)
  else
    # :nocov:
    Sequel::Deprecation.deprecate("Dataset#prepare will change to requiring a name argument in Sequel 5, please update your code.") unless name
    # :nocov:
  end

  ps
end

Protected Instance Methods

to_prepared_statement(type, values=nil, opts=OPTS) click to toggle source

Return a cloned copy of the current dataset extended with PreparedStatementMethods, setting the type and modify values.

# File lib/sequel/dataset/prepared_statements.rb, line 351
def to_prepared_statement(type, values=nil, opts=OPTS)
  mods = opts[:extend] || []
  mods += [PreparedStatementMethods]

  bind.
    clone(:prepared_statement_name=>opts[:name], :prepared_type=>type, :prepared_modify_values=>values, :orig_dataset=>self, :no_cache_sql=>true, :prepared_args=>@opts[:prepared_args]||[]).
    with_extend(*mods)
end

Private Instance Methods

allow_preparing_prepared_statements?() click to toggle source

Don't allow preparing prepared statements by default.

# File lib/sequel/dataset/prepared_statements.rb, line 363
def allow_preparing_prepared_statements?
  false
end
bound_variable_modules() click to toggle source
# File lib/sequel/dataset/prepared_statements.rb, line 367
def bound_variable_modules
  prepared_statement_modules
end
prepared_arg_placeholder() click to toggle source

The argument placeholder. Most databases used unnumbered arguments with question marks, so that is the default.

# File lib/sequel/dataset/prepared_statements.rb, line 377
def prepared_arg_placeholder
  PREPARED_ARG_PLACEHOLDER
end
prepared_statement_modules() click to toggle source
# File lib/sequel/dataset/prepared_statements.rb, line 371
def prepared_statement_modules
  []
end

9 - Internal Methods relating to SQL Creation

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Constants

ALL
AND_SEPARATOR
APOS
APOS_RE
ARRAY_EMPTY
AS
ASC
BACKSLASH
BITCOMP_CLOSE
BITCOMP_OPEN
BITWISE_METHOD_MAP
BOOL_FALSE
BOOL_TRUE
BRACKET_CLOSE
BRACKET_OPEN
CASE_ELSE
CASE_END
CASE_OPEN
CASE_THEN
CASE_WHEN
CAST_OPEN
COLON
COLUMN_REF_RE1
COLUMN_REF_RE2
COLUMN_REF_RE3
COMMA
COMMA_SEPARATOR
CONDITION_FALSE
CONDITION_TRUE
COUNT_FROM_SELF_OPTS
COUNT_OF_ALL_AS_COUNT
DATASET_ALIAS_BASE_NAME
DATETIME_SECFRACTION_ARG
DEFAULT
DEFAULT_VALUES
DELETE
DESC
DISTINCT
DOT
DOUBLE_APOS
DOUBLE_QUOTE
EMPTY_PARENS
EMULATED_FUNCTION_MAP

Map of emulated function names to native function names.

EQUAL
ESCAPE
EXISTS
EXTRACT
FILTER
FORMAT_DATE
FORMAT_DATE_STANDARD
FORMAT_OFFSET
FORMAT_TIMESTAMP_RE
FORMAT_USEC
FOR_UPDATE
FRAME_ALL
FRAME_ROWS
FROM
FUNCTION_DISTINCT
GROUP_BY
HAVING
INSERT
INTO
IS_LITERALS
IS_OPERATORS
LATERAL
LIKE_OPERATORS
LIMIT
NOT_SPACE
NULL
NULLS_FIRST
NULLS_LAST
N_ARITY_OPERATORS
OFFSET
ON
ON_PAREN
ORDER_BY
ORDER_BY_NS
OVER
PAREN_CLOSE
PAREN_OPEN
PAREN_SPACE_OPEN
PARTITION_BY
QUALIFY_KEYS
QUESTION_MARK
QUESTION_MARK_RE
QUOTE
QUOTE_RE
REGEXP_OPERATORS
RETURNING
SELECT
SET
SPACE
SPACE_WITH
SQL_WITH
STANDARD_TIMESTAMP_FORMAT
TILDE
TIMESTAMP_FORMAT
TWO_ARITY_OPERATORS
UNDERSCORE
UNION_ALL_SELECT
UPDATE
USING
VALUES
WHERE
WILDCARD
WITHIN_GROUP
WITH_ORDINALITY

Public Class Methods

clause_methods(type, clauses) click to toggle source

Given a type (e.g. select) and an array of clauses, return an array of methods to call to build the SQL string.

# File lib/sequel/dataset/sql.rb, line 184
def self.clause_methods(type, clauses)
  clauses.map{|clause| :"#{type}_#{clause}_sql"}.freeze
end
def_sql_method(mod, type, clauses) click to toggle source

Define a dataset literalization method for the given type in the given module, using the given clauses.

Arguments:

mod

Module in which to define method

type

Type of SQL literalization method to create, either :select, :insert, :update, or :delete

clauses

array of clauses that make up the SQL query for the type. This can either be a single array of symbols/strings, or it can be an array of pairs, with the first element in each pair being an if/elsif/else code fragment, and the second element in each pair being an array of symbol/strings for the appropriate branch.

# File lib/sequel/dataset/sql.rb, line 198
def self.def_sql_method(mod, type, clauses)
  priv = type == :update || type == :insert
  cacheable = type == :select || type == :delete

  lines = []
  lines << 'private' if priv
  lines << "def #{'_' if priv}#{type}_sql"
  lines << 'if sql = opts[:sql]; return static_sql(sql) end' unless priv
  lines << "if sql = cache_get(:_#{type}_sql); return sql end" if cacheable
  lines << 'check_modification_allowed!' if type == :delete
  lines << 'sql = @opts[:append_sql] || sql_string_origin'

  if clauses.all?{|c| c.is_a?(Array)}
    clauses.each do |i, cs|
      lines << i
      lines.concat(clause_methods(type, cs).map{|x| "#{x}(sql)"}) 
    end 
    lines << 'end'
  else
    lines.concat(clause_methods(type, clauses).map{|x| "#{x}(sql)"})
  end

  lines << "cache_set(:_#{type}_sql, sql) if cache_sql?" if cacheable
  lines << 'sql'
  lines << 'end'

  mod.class_eval lines.join("\n"), __FILE__, __LINE__
end

Public Instance Methods

aliased_expression_sql_append(sql, ae) click to toggle source

Append literalization of aliased expression to SQL string.

# File lib/sequel/dataset/sql.rb, line 354
def aliased_expression_sql_append(sql, ae)
  literal_append(sql, ae.expression)
  as_sql_append(sql, ae.alias, ae.columns)
end
array_sql_append(sql, a) click to toggle source

Append literalization of array to SQL string.

# File lib/sequel/dataset/sql.rb, line 360
def array_sql_append(sql, a)
  if a.empty?
    sql << ARRAY_EMPTY
  else
    sql << PAREN_OPEN
    expression_list_append(sql, a)
    sql << PAREN_CLOSE
  end
end
boolean_constant_sql_append(sql, constant) click to toggle source

Append literalization of boolean constant to SQL string.

# File lib/sequel/dataset/sql.rb, line 371
def boolean_constant_sql_append(sql, constant)
  if (constant == true || constant == false) && !supports_where_true?
    sql << (constant == true ? CONDITION_TRUE : CONDITION_FALSE)
  else
    literal_append(sql, constant)
  end
end
case_expression_sql_append(sql, ce) click to toggle source

Append literalization of case expression to SQL string.

# File lib/sequel/dataset/sql.rb, line 380
def case_expression_sql_append(sql, ce)
  sql << CASE_OPEN
  if ce.expression?
    sql << SPACE
    literal_append(sql, ce.expression)
  end
  w = CASE_WHEN
  t = CASE_THEN
  ce.conditions.each do |c,r|
    sql << w
    literal_append(sql, c)
    sql << t
    literal_append(sql, r)
  end
  sql << CASE_ELSE
  literal_append(sql, ce.default)
  sql << CASE_END
end
cast_sql_append(sql, expr, type) click to toggle source

Append literalization of cast expression to SQL string.

# File lib/sequel/dataset/sql.rb, line 400
def cast_sql_append(sql, expr, type)
  sql << CAST_OPEN
  literal_append(sql, expr)
  sql << AS << db.cast_type_literal(type).to_s
  sql << PAREN_CLOSE
end
column_all_sql_append(sql, ca) click to toggle source

Append literalization of column all selection to SQL string.

# File lib/sequel/dataset/sql.rb, line 408
def column_all_sql_append(sql, ca)
  qualified_identifier_sql_append(sql, ca.table, WILDCARD)
end
complex_expression_sql_append(sql, op, args) click to toggle source

Append literalization of complex expression to SQL string.

# File lib/sequel/dataset/sql.rb, line 413
def complex_expression_sql_append(sql, op, args)
  case op
  when *IS_OPERATORS
    r = args.at(1)
    if r.nil? || supports_is_true?
      raise(InvalidOperation, 'Invalid argument used for IS operator') unless val = IS_LITERALS[r]
      sql << PAREN_OPEN
      literal_append(sql, args.at(0))
      sql << SPACE << op.to_s << SPACE
      sql << val << PAREN_CLOSE
    elsif op == :IS
      complex_expression_sql_append(sql, :"=", args)
    else
      complex_expression_sql_append(sql, :OR, [SQL::BooleanExpression.new(:"!=", *args), SQL::BooleanExpression.new(:IS, args.at(0), nil)])
    end
  when :IN, :"NOT IN"
    cols = args.at(0)
    vals = args.at(1)
    col_array = true if cols.is_a?(Array)
    if vals.is_a?(Array)
      val_array = true
      empty_val_array = vals == []
    end
    if empty_val_array
      literal_append(sql, empty_array_value(op, cols))
    elsif col_array
      if !supports_multiple_column_in?
        if val_array
          expr = SQL::BooleanExpression.new(:OR, *vals.to_a.map{|vs| SQL::BooleanExpression.from_value_pairs(cols.to_a.zip(vs).map{|c, v| [c, v]})})
          literal_append(sql, op == :IN ? expr : ~expr)
        else
          old_vals = vals
          vals = vals.naked if vals.is_a?(Sequel::Dataset)
          vals = vals.to_a
          val_cols = old_vals.columns
          complex_expression_sql_append(sql, op, [cols, vals.map!{|x| x.values_at(*val_cols)}])
        end
      else
        # If the columns and values are both arrays, use array_sql instead of
        # literal so that if values is an array of two element arrays, it
        # will be treated as a value list instead of a condition specifier.
        sql << PAREN_OPEN
        literal_append(sql, cols)
        sql << SPACE << op.to_s << SPACE
        if val_array
          array_sql_append(sql, vals)
        else
          literal_append(sql, vals)
        end
        sql << PAREN_CLOSE
      end
    else
      sql << PAREN_OPEN
      literal_append(sql, cols)
      sql << SPACE << op.to_s << SPACE
      literal_append(sql, vals)
      sql << PAREN_CLOSE
    end
  when :LIKE, :'NOT LIKE'
    sql << PAREN_OPEN
    literal_append(sql, args.at(0))
    sql << SPACE << op.to_s << SPACE
    literal_append(sql, args.at(1))
    sql << ESCAPE
    literal_append(sql, BACKSLASH)
    sql << PAREN_CLOSE
  when :ILIKE, :'NOT ILIKE'
    complex_expression_sql_append(sql, (op == :ILIKE ? :LIKE : :"NOT LIKE"), args.map{|v| Sequel.function(:UPPER, v)})
  when :**
    function_sql_append(sql, Sequel.function(:power, *args))
  when *TWO_ARITY_OPERATORS
    if REGEXP_OPERATORS.include?(op) && !supports_regexp?
      raise InvalidOperation, "Pattern matching via regular expressions is not supported on #{db.database_type}"
    end
    sql << PAREN_OPEN
    literal_append(sql, args.at(0))
    sql << SPACE << op.to_s << SPACE
    literal_append(sql, args.at(1))
    sql << PAREN_CLOSE
  when *N_ARITY_OPERATORS
    sql << PAREN_OPEN
    c = false
    op_str = " #{op} "
    args.each do |a|
      sql << op_str if c
      literal_append(sql, a)
      c ||= true
    end
    sql << PAREN_CLOSE
  when :NOT
    sql << NOT_SPACE
    literal_append(sql, args.at(0))
  when :NOOP
    literal_append(sql, args.at(0))
  when :'B~'
    sql << TILDE
    literal_append(sql, args.at(0))
  when :extract
    sql << EXTRACT << args.at(0).to_s << FROM
    literal_append(sql, args.at(1))
    sql << PAREN_CLOSE
  else
    raise(InvalidOperation, "invalid operator #{op}")
  end
end
constant_sql_append(sql, constant) click to toggle source

Append literalization of constant to SQL string.

# File lib/sequel/dataset/sql.rb, line 520
def constant_sql_append(sql, constant)
  sql << constant.to_s
end
delayed_evaluation_sql_append(sql, delay) click to toggle source

Append literalization of delayed evaluation to SQL string, causing the delayed evaluation proc to be evaluated.

# File lib/sequel/dataset/sql.rb, line 526
def delayed_evaluation_sql_append(sql, delay)
  # Delayed evaluations are used specifically so the SQL
  # can differ in subsequent calls, so we definitely don't
  # want to cache the sql in this case.
  disable_sql_caching!

  if recorder = @opts[:placeholder_literalizer]
    recorder.use(sql, lambda{delay.call(self)}, nil)
  else
    literal_append(sql, delay.call(self))
  end
end
function_sql_append(sql, f) click to toggle source

Append literalization of function call to SQL string.

# File lib/sequel/dataset/sql.rb, line 540
def function_sql_append(sql, f)
  name = f.name
  opts = f.opts

  if opts[:emulate]
    if emulate_function?(name)
      emulate_function_sql_append(sql, f)
      return
    end

    name = native_function_name(name) 
  end

  sql << LATERAL if opts[:lateral]

  case name
  when SQL::Identifier
    if supports_quoted_function_names? && opts[:quoted] != false
      literal_append(sql, name)
    else
      sql << name.value.to_s
    end
  when SQL::QualifiedIdentifier
    if supports_quoted_function_names? && opts[:quoted] != false
      literal_append(sql, name)
    else
      sql << split_qualifiers(name).join(DOT)
    end
  else
    if supports_quoted_function_names? && opts[:quoted]
      quote_identifier_append(sql, name)
    else
      sql << name.to_s
    end
  end

  sql << PAREN_OPEN
  if opts[:*]
    sql << WILDCARD
  else
    sql << FUNCTION_DISTINCT if opts[:distinct]
    expression_list_append(sql, f.args)
    if order = opts[:order]
      sql << ORDER_BY
      expression_list_append(sql, order)
    end
  end
  sql << PAREN_CLOSE

  if group = opts[:within_group]
    sql << WITHIN_GROUP
    expression_list_append(sql, group)
    sql << PAREN_CLOSE
  end

  if filter = opts[:filter]
    sql << FILTER
    literal_append(sql, filter_expr(filter, &opts[:filter_block]))
    sql << PAREN_CLOSE
  end

  if window = opts[:over]
    sql << OVER
    window_sql_append(sql, window.opts)
  end

  if opts[:with_ordinality]
    sql << WITH_ORDINALITY
  end
end
join_clause_sql_append(sql, jc) click to toggle source

Append literalization of JOIN clause without ON or USING to SQL string.

# File lib/sequel/dataset/sql.rb, line 612
def join_clause_sql_append(sql, jc)
  table = jc.table
  table_alias = jc.table_alias
  table_alias = nil if table == table_alias && !jc.column_aliases
  sql << SPACE << join_type_sql(jc.join_type) << SPACE
  identifier_append(sql, table)
  as_sql_append(sql, table_alias, jc.column_aliases) if table_alias
end
join_on_clause_sql_append(sql, jc) click to toggle source

Append literalization of JOIN ON clause to SQL string.

# File lib/sequel/dataset/sql.rb, line 622
def join_on_clause_sql_append(sql, jc)
  join_clause_sql_append(sql, jc)
  sql << ON
  literal_append(sql, filter_expr(jc.on))
end
join_using_clause_sql_append(sql, jc) click to toggle source

Append literalization of JOIN USING clause to SQL string.

# File lib/sequel/dataset/sql.rb, line 629
def join_using_clause_sql_append(sql, jc)
  join_clause_sql_append(sql, jc)
  sql << USING
  column_list_append(sql, jc.using)
  sql << PAREN_CLOSE
end
negative_boolean_constant_sql_append(sql, constant) click to toggle source

Append literalization of negative boolean constant to SQL string.

# File lib/sequel/dataset/sql.rb, line 637
def negative_boolean_constant_sql_append(sql, constant)
  sql << NOT_SPACE
  boolean_constant_sql_append(sql, constant)
end
ordered_expression_sql_append(sql, oe) click to toggle source

Append literalization of ordered expression to SQL string.

# File lib/sequel/dataset/sql.rb, line 643
def ordered_expression_sql_append(sql, oe)
  literal_append(sql, oe.expression)
  sql << (oe.descending ? DESC : ASC)
  case oe.nulls
  when :first
    sql << NULLS_FIRST
  when :last
    sql << NULLS_LAST
  end
end
placeholder_literal_string_sql_append(sql, pls) click to toggle source

Append literalization of placeholder literal string to SQL string.

# File lib/sequel/dataset/sql.rb, line 655
def placeholder_literal_string_sql_append(sql, pls)
  args = pls.args
  str = pls.str
  sql << PAREN_OPEN if pls.parens
  if args.is_a?(Hash)
    if args.empty?
      sql << str
    else
      re = /:(#{args.keys.map{|k| Regexp.escape(k.to_s)}.join('|')})\b/
      loop do
        previous, q, str = str.partition(re)
        sql << previous
        literal_append(sql, args[($1||q[1..-1].to_s).to_sym]) unless q.empty?
        break if str.empty?
      end
    end
  elsif str.is_a?(Array)
    len = args.length
    str.each_with_index do |s, i|
      sql << s
      literal_append(sql, args[i]) unless i == len
    end
    unless str.length == args.length || str.length == args.length + 1
      raise Error, "Mismatched number of placeholders (#{str.length}) and placeholder arguments (#{args.length}) when using placeholder array"
    end
  else
    i = -1
    match_len = args.length - 1
    loop do
      previous, q, str = str.partition(QUESTION_MARK)
      sql << previous
      literal_append(sql, args.at(i+=1)) unless q.empty?
      if str.empty?
        unless i == match_len
          raise Error, "Mismatched number of placeholders (#{i+1}) and placeholder arguments (#{args.length}) when using placeholder array"
        end
        break
      end
    end
  end
  sql << PAREN_CLOSE if pls.parens
end
qualified_identifier_sql_append(sql, table, column=(c = table.column; table = table.table; c)) click to toggle source

Append literalization of qualified identifier to SQL string. If 3 arguments are given, the 2nd should be the table/qualifier and the third should be column/qualified. If 2 arguments are given, the 2nd should be an SQL::QualifiedIdentifier.

# File lib/sequel/dataset/sql.rb, line 701
def qualified_identifier_sql_append(sql, table, column=(c = table.column; table = table.table; c))
  identifier_append(sql, table)
  sql << DOT
  identifier_append(sql, column)
end
quote_identifier_append(sql, name) click to toggle source

Append literalization of unqualified identifier to SQL string. Adds quoting to identifiers (columns and tables). If identifiers are not being quoted, returns name as a string. If identifiers are being quoted quote the name with quoted_identifier.

# File lib/sequel/dataset/sql.rb, line 711
def quote_identifier_append(sql, name)
  if name.is_a?(LiteralString)
    sql << name
  else
    name = name.value if name.is_a?(SQL::Identifier)
    name = input_identifier(name)
    if quote_identifiers?
      quoted_identifier_append(sql, name)
    else
      sql << name
    end
  end
end
quote_schema_table_append(sql, table) click to toggle source

Append literalization of identifier or unqualified identifier to SQL string.

# File lib/sequel/dataset/sql.rb, line 726
def quote_schema_table_append(sql, table)
  schema, table = schema_and_table(table)
  if schema
    quote_identifier_append(sql, schema)
    sql << DOT
  end
  quote_identifier_append(sql, table)
end
quoted_identifier_append(sql, name) click to toggle source

Append literalization of quoted identifier to SQL string. This method quotes the given name with the SQL standard double quote. should be overridden by subclasses to provide quoting not matching the SQL standard, such as backtick (used by MySQL and SQLite).

# File lib/sequel/dataset/sql.rb, line 739
def quoted_identifier_append(sql, name)
  sql << QUOTE << name.to_s.gsub(QUOTE_RE, DOUBLE_QUOTE) << QUOTE
end
schema_and_table(table_name, sch=nil) click to toggle source

Split the schema information from the table, returning two strings, one for the schema and one for the table. The returned schema may be nil, but the table will always have a string value.

Note that this function does not handle tables with more than one level of qualification (e.g. database.schema.table on Microsoft SQL Server).

# File lib/sequel/dataset/sql.rb, line 750
def schema_and_table(table_name, sch=nil)
  sch = sch.to_s if sch
  case table_name
  when Symbol
    s, t, _ = split_symbol(table_name)
    [s||sch, t]
  when SQL::QualifiedIdentifier
    [table_name.table.to_s, table_name.column.to_s]
  when SQL::Identifier
    [sch, table_name.value.to_s]
  when String
    [sch, table_name]
  else
    raise Error, 'table_name should be a Symbol, SQL::QualifiedIdentifier, SQL::Identifier, or String'
  end
end
split_qualifiers(table_name, *args) click to toggle source

Splits table_name into an array of strings.

ds.split_qualifiers(:s) # ['s']
ds.split_qualifiers(:t__s) # ['t', 's']
ds.split_qualifiers(Sequel[:d][:t__s]) # ['d', 't', 's']
ds.split_qualifiers(Sequel[:h__d][:t__s]) # ['h', 'd', 't', 's']
# File lib/sequel/dataset/sql.rb, line 773
def split_qualifiers(table_name, *args)
  case table_name
  when SQL::QualifiedIdentifier
    split_qualifiers(table_name.table, nil) + split_qualifiers(table_name.column, nil)
  else
    sch, table = schema_and_table(table_name, *args)
    sch ? [sch, table] : [table]
  end
end
subscript_sql_append(sql, s) click to toggle source

Append literalization of subscripts (SQL array accesses) to SQL string.

# File lib/sequel/dataset/sql.rb, line 784
def subscript_sql_append(sql, s)
  literal_append(sql, s.f)
  sql << BRACKET_OPEN
  if s.sub.length == 1 && (range = s.sub.first).is_a?(Range)
    literal_append(sql, range.begin)
    sql << COLON
    e = range.end
    e -= 1 if range.exclude_end? && e.is_a?(Integer)
    literal_append(sql, e)
  else
    expression_list_append(sql, s.sub)
  end
  sql << BRACKET_CLOSE
end
window_sql_append(sql, opts) click to toggle source

Append literalization of windows (for window functions) to SQL string.

# File lib/sequel/dataset/sql.rb, line 800
def window_sql_append(sql, opts)
  raise(Error, 'This dataset does not support window functions') unless supports_window_functions?
  sql << PAREN_OPEN
  window, part, order, frame = opts.values_at(:window, :partition, :order, :frame)
  space = false
  space_s = SPACE
  if window
    literal_append(sql, window)
    space = true
  end
  if part
    sql << space_s if space
    sql << PARTITION_BY
    expression_list_append(sql, Array(part))
    space = true
  end
  if order
    sql << space_s if space
    sql << ORDER_BY_NS
    expression_list_append(sql, Array(order))
    space = true
  end
  case frame
    when nil
      # nothing
    when :all
      sql << space_s if space
      sql << FRAME_ALL
    when :rows
      sql << space_s if space
      sql << FRAME_ROWS
    when String
      sql << space_s if space
      sql << frame
    else
      raise Error, "invalid window frame clause, should be :all, :rows, a string, or nil"
  end
  sql << PAREN_CLOSE
end

Protected Instance Methods

compound_from_self() click to toggle source

Return a from_self dataset if an order or limit is specified, so it works as expected with UNION, EXCEPT, and INTERSECT clauses.

# File lib/sequel/dataset/sql.rb, line 844
def compound_from_self
  (@opts[:sql] || @opts[:limit] || @opts[:order]) ? from_self : self
end

Private Instance Methods

_truncate_sql(table) click to toggle source

Formats the truncate statement. Assumes the table given has already been literalized.

# File lib/sequel/dataset/sql.rb, line 852
def _truncate_sql(table)
  "TRUNCATE TABLE #{table}"
end
aggregate_dataset() click to toggle source

Clone of this dataset usable in aggregate operations. Does a from_self if dataset contains any parameters that would affect normal aggregation, or just removes an existing order if not.

# File lib/sequel/dataset/sql.rb, line 895
def aggregate_dataset
  options_overlap(COUNT_FROM_SELF_OPTS) ? from_self : unordered
end
alias_alias_symbol(s) click to toggle source

Returns an appropriate symbol for the alias represented by s.

# File lib/sequel/dataset/sql.rb, line 857
def alias_alias_symbol(s)
  case s
  when Symbol
    s
  when String
    s.to_sym
  when SQL::Identifier
    s.value.to_s.to_sym
  else
    raise Error, "Invalid alias for alias_alias_symbol: #{s.inspect}"
  end
end
alias_symbol(sym) click to toggle source

Returns an appropriate alias symbol for the given object, which can be a Symbol, String, SQL::Identifier, SQL::QualifiedIdentifier, or SQL::AliasedExpression.

# File lib/sequel/dataset/sql.rb, line 873
def alias_symbol(sym)
  case sym
  when Symbol
    s, t, a = split_symbol(sym)
    a || s ? (a || t).to_sym : sym
  when String
    sym.to_sym
  when SQL::Identifier
    sym.value.to_s.to_sym
  when SQL::QualifiedIdentifier
    alias_symbol(sym.column)
  when SQL::AliasedExpression
    alias_alias_symbol(sym.alias)
  else
    raise Error, "Invalid alias for alias_symbol: #{sym.inspect}"
  end
end
as_sql_append(sql, aliaz, column_aliases=nil) click to toggle source

Append aliasing expression to SQL string.

# File lib/sequel/dataset/sql.rb, line 900
def as_sql_append(sql, aliaz, column_aliases=nil)
  sql << AS
  quote_identifier_append(sql, aliaz)
  if column_aliases
    raise Error, "#{db.database_type} does not support derived column lists" unless supports_derived_column_lists?
    sql << PAREN_OPEN
    identifier_list_append(sql, column_aliases)
    sql << PAREN_CLOSE
  end
end
cache_sql?() click to toggle source

Only allow caching the select SQL if the dataset is frozen and hasn't specifically been marked as not allowing SQL caching.

# File lib/sequel/dataset/sql.rb, line 913
def cache_sql?
  frozen? && !@opts[:no_cache_sql] && !cache_get(:_no_cache_sql)
end
check_modification_allowed!() click to toggle source

Raise an InvalidOperation exception if deletion is not allowed for this dataset

# File lib/sequel/dataset/sql.rb, line 919
def check_modification_allowed!
  raise(InvalidOperation, "Grouped datasets cannot be modified") if opts[:group]
  raise(InvalidOperation, "Joined datasets cannot be modified") if !supports_modifying_joins? && joined_dataset?
end
check_truncation_allowed!() click to toggle source

Alias of check_modification_allowed!

# File lib/sequel/dataset/sql.rb, line 925
def check_truncation_allowed!
  check_modification_allowed!
end
column_list_append(sql, columns) click to toggle source

Append column list to SQL string. Converts an array of column names into a comma seperated string of column names. If the array is empty, a wildcard (*) is returned.

# File lib/sequel/dataset/sql.rb, line 932
def column_list_append(sql, columns)
  if (columns.nil? || columns.empty?)
    sql << WILDCARD
  else
    expression_list_append(sql, columns)
  end
end
complex_expression_arg_pairs(args) { |at, at| ... } click to toggle source

Yield each pair of arguments to the block, which should return an object representing the SQL expression for those two arguments. For more than two arguments, the first argument to the block will be result of the previous block call.

# File lib/sequel/dataset/sql.rb, line 944
def complex_expression_arg_pairs(args)
  case args.length
  when 1
    args.at(0)
  when 2
    yield args.at(0), args.at(1)
  else
    args.inject{|m, a| yield(m, a)}
  end
end
complex_expression_arg_pairs_append(sql, args, &block) click to toggle source

Append the literalization of the args using #complex_expression_arg_pairs to the given SQL string, used when database operator/function is 2-ary where Sequel expression is N-ary.

# File lib/sequel/dataset/sql.rb, line 958
def complex_expression_arg_pairs_append(sql, args, &block)
  literal_append(sql, complex_expression_arg_pairs(args, &block))
end
complex_expression_emulate_append(sql, op, args) click to toggle source

Append literalization of complex expression to SQL string, for operators unsupported by some databases. Used by adapters for databases that don't support the operators natively.

# File lib/sequel/dataset/sql.rb, line 965
def complex_expression_emulate_append(sql, op, args)
  case op
  when :%
    complex_expression_arg_pairs_append(sql, args){|a, b| Sequel.function(:MOD, a, b)}
  when :>>
    complex_expression_arg_pairs_append(sql, args){|a, b| Sequel./(a, Sequel.function(:power, 2, b))}
  when :<<
    complex_expression_arg_pairs_append(sql, args){|a, b| Sequel.*(a, Sequel.function(:power, 2, b))}
  when :&, :|, :^
    f = BITWISE_METHOD_MAP[op]
    complex_expression_arg_pairs_append(sql, args){|a, b| Sequel.function(f, a, b)}
  when :'B~'
    sql << BITCOMP_OPEN
    literal_append(sql, args.at(0))
    sql << BITCOMP_CLOSE
  end
end
compound_dataset_sql_append(sql, ds) click to toggle source

Append literalization of dataset used in UNION/INTERSECT/EXCEPT clause to SQL string.

# File lib/sequel/dataset/sql.rb, line 984
def compound_dataset_sql_append(sql, ds)
  subselect_sql_append(sql, ds)
end
dataset_alias(number) click to toggle source

The alias to use for datasets, takes a number to make sure the name is unique.

# File lib/sequel/dataset/sql.rb, line 989
def dataset_alias(number)
  :"#{DATASET_ALIAS_BASE_NAME}#{number}"
end
default_timestamp_format() click to toggle source

The strftime format to use when literalizing the time.

# File lib/sequel/dataset/sql.rb, line 994
def default_timestamp_format
  requires_sql_standard_datetimes? ? STANDARD_TIMESTAMP_FORMAT : TIMESTAMP_FORMAT
end
delete_delete_sql(sql) click to toggle source
# File lib/sequel/dataset/sql.rb, line 998
def delete_delete_sql(sql)
  sql << DELETE
end
delete_from_sql(sql) click to toggle source
# File lib/sequel/dataset/sql.rb, line 1002
def delete_from_sql(sql)
  if f = @opts[:from]
    sql << FROM
    source_list_append(sql, f)
  end
end
delete_order_sql(sql)
Alias for: select_order_sql
delete_returning_sql(sql)
delete_where_sql(sql)
Alias for: select_where_sql
delete_with_sql(sql)
Alias for: select_with_sql
disable_sql_caching!() click to toggle source

Disable caching of SQL for the current dataset

# File lib/sequel/dataset/sql.rb, line 1010
def disable_sql_caching!
  cache_set(:_no_cache_sql, true)
end
empty_array_value(op, cols) click to toggle source

An expression for how to handle an empty array lookup.

# File lib/sequel/dataset/sql.rb, line 1053
def empty_array_value(op, cols)
  {1 => ((op == :IN) ? 0 : 1)}
end
empty_from_sql() click to toggle source

An SQL FROM clause to use in SELECT statements where the dataset has no from tables.

# File lib/sequel/dataset/sql.rb, line 1016
def empty_from_sql
  nil
end
emulate_function?(name) click to toggle source

Whether to emulate the function with the given name. This should only be true if the emulation goes beyond choosing a function with a different name.

# File lib/sequel/dataset/sql.rb, line 1022
def emulate_function?(name)
  false
end
expression_list_append(sql, columns) click to toggle source

Append literalization of array of expressions to SQL string.

# File lib/sequel/dataset/sql.rb, line 1027
def expression_list_append(sql, columns)
  c = false
  co = COMMA
  columns.each do |col|
    sql << co if c
    literal_append(sql, col)
    c ||= true
  end
end
format_timestamp(v) click to toggle source

Format the timestamp based on the #default_timestamp_format, with a couple of modifiers. First, allow %N to be used for fractions seconds (if the database supports them), and override %z to always use a numeric offset of hours and minutes.

# File lib/sequel/dataset/sql.rb, line 1061
def format_timestamp(v)
  v2 = db.from_application_timestamp(v)
  fmt = default_timestamp_format.gsub(FORMAT_TIMESTAMP_RE) do |m|
    if m == FORMAT_USEC
      format_timestamp_usec(v.is_a?(DateTime) ? v.sec_fraction*(DATETIME_SECFRACTION_ARG) : v.usec) if supports_timestamp_usecs?
    else
      if supports_timestamp_timezones?
        # Would like to just use %z format, but it doesn't appear to work on Windows
        # Instead, the offset fragment is constructed manually
        minutes = (v2.is_a?(DateTime) ? v2.offset * 1440 : v2.utc_offset/60).to_i
        format_timestamp_offset(*minutes.divmod(60))
      end
    end
  end
  v2.strftime(fmt)
end
format_timestamp_offset(hour, minute) click to toggle source

Return the SQL timestamp fragment to use for the timezone offset.

# File lib/sequel/dataset/sql.rb, line 1079
def format_timestamp_offset(hour, minute)
  sprintf(FORMAT_OFFSET, hour, minute)
end
format_timestamp_usec(usec) click to toggle source

Return the SQL timestamp fragment to use for the fractional time part. Should start with the decimal point. Uses 6 decimal places by default.

# File lib/sequel/dataset/sql.rb, line 1085
def format_timestamp_usec(usec)
  unless (ts = timestamp_precision) == 6
    usec = usec/(10 ** (6 - ts))
  end
  sprintf(".%0#{ts}d", usec)
end
grouping_element_list_append(sql, columns) click to toggle source

Append literalization of array of grouping elements to SQL string.

# File lib/sequel/dataset/sql.rb, line 1038
def grouping_element_list_append(sql, columns)
  c = false
  co = COMMA
  columns.each do |col|
    sql << co if c
    if col.is_a?(Array) && col.empty?
      sql << EMPTY_PARENS
    else
      literal_append(sql, Array(col))
    end
    c ||= true
  end
end
identifier_append(sql, v) click to toggle source

Append literalization of identifier to SQL string, considering regular strings as SQL identifiers instead of SQL strings.

# File lib/sequel/dataset/sql.rb, line 1094
def identifier_append(sql, v)
  if v.is_a?(String)
    case v
    when LiteralString
      sql << v
    when SQL::Blob
      literal_append(sql, v)
    else
      quote_identifier_append(sql, v)
    end
  else
    literal_append(sql, v)
  end
end
identifier_list_append(sql, args) click to toggle source

Append literalization of array of identifiers to SQL string.

# File lib/sequel/dataset/sql.rb, line 1110
def identifier_list_append(sql, args)
  c = false
  comma = COMMA
  args.each do |a|
    sql << comma if c
    identifier_append(sql, a)
    c ||= true
  end
end
input_identifier(v) click to toggle source

Upcase identifiers by default when inputting them into the database.

# File lib/sequel/dataset/sql.rb, line 1121
def input_identifier(v)
  v.to_s.upcase
end
insert_columns_sql(sql) click to toggle source
# File lib/sequel/dataset/sql.rb, line 1134
def insert_columns_sql(sql)
  columns = opts[:columns]
  if columns && !columns.empty?
    sql << PAREN_SPACE_OPEN
    identifier_list_append(sql, columns)
    sql << PAREN_CLOSE
  end 
end
insert_empty_columns_values() click to toggle source

The columns and values to use for an empty insert if the database doesn't support INSERT with DEFAULT VALUES.

# File lib/sequel/dataset/sql.rb, line 1145
def insert_empty_columns_values
  [[columns.last], [DEFAULT]]
end
insert_insert_sql(sql) click to toggle source
# File lib/sequel/dataset/sql.rb, line 1149
def insert_insert_sql(sql)
  sql << INSERT
end
insert_into_sql(sql) click to toggle source
# File lib/sequel/dataset/sql.rb, line 1125
def insert_into_sql(sql)
  sql << INTO
  if (f = @opts[:from]) && f.length == 1
    identifier_append(sql, unaliased_identifier(f.first))
  else
    source_list_append(sql, f)
  end
end
insert_returning_sql(sql) click to toggle source
# File lib/sequel/dataset/sql.rb, line 1172
def insert_returning_sql(sql)
  if opts.has_key?(:returning)
    sql << RETURNING
    column_list_append(sql, Array(opts[:returning]))
  end
end
insert_values_sql(sql) click to toggle source
# File lib/sequel/dataset/sql.rb, line 1153
def insert_values_sql(sql)
  case values = opts[:values]
  when Array
    if values.empty?
      sql << DEFAULT_VALUES
    else
      sql << VALUES
      literal_append(sql, values)
    end
  when Dataset
    sql << SPACE
    subselect_sql_append(sql, values)
  when LiteralString
    sql << SPACE << values
  else
    raise Error, "Unsupported INSERT values type, should be an Array or Dataset: #{values.inspect}"
  end
end
insert_with_sql(sql)
Alias for: select_with_sql
join_type_sql(join_type) click to toggle source

SQL fragment specifying a JOIN type, converts underscores to spaces and upcases.

# File lib/sequel/dataset/sql.rb, line 1183
def join_type_sql(join_type)
  "#{join_type.to_s.gsub(UNDERSCORE, SPACE).upcase} JOIN"
end
literal_array_append(sql, v) click to toggle source

Append a literalization of the array to SQL string. Treats as an expression if an array of all two pairs, or as a SQL array otherwise.

# File lib/sequel/dataset/sql.rb, line 1189
def literal_array_append(sql, v)
  if Sequel.condition_specifier?(v)
    literal_expression_append(sql, SQL::BooleanExpression.from_value_pairs(v))
  else
    array_sql_append(sql, v)
  end
end
literal_big_decimal(v) click to toggle source

SQL fragment for BigDecimal

# File lib/sequel/dataset/sql.rb, line 1198
def literal_big_decimal(v)
  d = v.to_s("F")
  v.nan? || v.infinite? ?  "'#{d}'" : d
end
literal_blob_append(sql, v) click to toggle source

Append literalization of SQL::Blob to SQL string.

# File lib/sequel/dataset/sql.rb, line 1204
def literal_blob_append(sql, v)
  literal_string_append(sql, v)
end
literal_dataset_append(sql, v) click to toggle source

Append literalization of dataset to SQL string. Does a subselect inside parantheses.

# File lib/sequel/dataset/sql.rb, line 1209
def literal_dataset_append(sql, v)
  sql << LATERAL if v.opts[:lateral]
  sql << PAREN_OPEN
  subselect_sql_append(sql, v)
  sql << PAREN_CLOSE
end
literal_date(v) click to toggle source

SQL fragment for Date, using the ISO8601 format.

# File lib/sequel/dataset/sql.rb, line 1217
def literal_date(v)
  if requires_sql_standard_datetimes?
    v.strftime(FORMAT_DATE_STANDARD)
  else
    v.strftime(FORMAT_DATE)
  end
end
literal_datetime(v) click to toggle source

SQL fragment for DateTime

# File lib/sequel/dataset/sql.rb, line 1226
def literal_datetime(v)
  format_timestamp(v)
end
literal_datetime_append(sql, v) click to toggle source

Append literalization of DateTime to SQL string.

# File lib/sequel/dataset/sql.rb, line 1231
def literal_datetime_append(sql, v)
  sql << literal_datetime(v)
end
literal_expression_append(sql, v) click to toggle source

Append literalization of SQL::Expression to SQL string.

# File lib/sequel/dataset/sql.rb, line 1236
def literal_expression_append(sql, v)
  v.to_s_append(self, sql)
end
literal_false() click to toggle source

SQL fragment for false

# File lib/sequel/dataset/sql.rb, line 1241
def literal_false
  BOOL_FALSE
end
literal_float(v) click to toggle source

SQL fragment for Float

# File lib/sequel/dataset/sql.rb, line 1246
def literal_float(v)
  v.to_s
end
literal_hash_append(sql, v) click to toggle source

Append literalization of Hash to SQL string, treating hash as a boolean expression.

# File lib/sequel/dataset/sql.rb, line 1251
def literal_hash_append(sql, v)
  literal_expression_append(sql, SQL::BooleanExpression.from_value_pairs(v))
end
literal_integer(v) click to toggle source

SQL fragment for Integer

# File lib/sequel/dataset/sql.rb, line 1256
def literal_integer(v)
  v.to_s
end
literal_nil() click to toggle source

SQL fragment for nil

# File lib/sequel/dataset/sql.rb, line 1261
def literal_nil
  NULL
end
literal_other_append(sql, v) click to toggle source

Append a literalization of the object to the given SQL string. Calls sql_literal_append if object responds to it, otherwise calls sql_literal if object responds to it, otherwise raises an error. If a database specific type is allowed, this should be overriden in a subclass.

# File lib/sequel/dataset/sql.rb, line 1269
def literal_other_append(sql, v)
  # We can't be sure if v will always literalize to the same SQL, so
  # don't cache SQL for a dataset that uses this.
  disable_sql_caching!

  if v.respond_to?(:sql_literal_append)
    v.sql_literal_append(self, sql)
  elsif v.respond_to?(:sql_literal)
    sql << v.sql_literal(self)
  else
    raise Error, "can't express #{v.inspect} as a SQL literal"
  end
end
literal_sqltime(v) click to toggle source

SQL fragment for Sequel::SQLTime, containing just the time part

# File lib/sequel/dataset/sql.rb, line 1284
def literal_sqltime(v)
  v.strftime("'%H:%M:%S#{format_timestamp_usec(v.usec) if supports_timestamp_usecs?}'")
end
literal_sqltime_append(sql, v) click to toggle source

Append literalization of Sequel::SQLTime to SQL string.

# File lib/sequel/dataset/sql.rb, line 1289
def literal_sqltime_append(sql, v)
  sql << literal_sqltime(v)
end
literal_string_append(sql, v) click to toggle source

Append literalization of string to SQL string.

# File lib/sequel/dataset/sql.rb, line 1294
def literal_string_append(sql, v)
  sql << APOS << v.gsub(APOS_RE, DOUBLE_APOS) << APOS
end
literal_symbol_append(sql, v) click to toggle source

Append literalization of symbol to SQL string.

# File lib/sequel/dataset/sql.rb, line 1299
def literal_symbol_append(sql, v)
  c_table, column, c_alias = split_symbol(v)
  if c_table
    quote_identifier_append(sql, c_table)
    sql << DOT
  end
  quote_identifier_append(sql, column)
  as_sql_append(sql, c_alias) if c_alias
end
literal_time(v) click to toggle source

SQL fragment for Time

# File lib/sequel/dataset/sql.rb, line 1310
def literal_time(v)
  format_timestamp(v)
end
literal_time_append(sql, v) click to toggle source

Append literalization of Time to SQL string.

# File lib/sequel/dataset/sql.rb, line 1315
def literal_time_append(sql, v)
  sql << literal_time(v)
end
literal_true() click to toggle source

SQL fragment for true

# File lib/sequel/dataset/sql.rb, line 1320
def literal_true
  BOOL_TRUE
end
multi_insert_sql_strategy() click to toggle source

What strategy to use for import/multi_insert. While SQL-92 defaults to allowing multiple rows in a VALUES clause, there are enough databases that don't allow that that it can't be the default. Use separate queries by default, which works everywhere.

# File lib/sequel/dataset/sql.rb, line 1328
def multi_insert_sql_strategy
  :separate
end
native_function_name(emulated_function) click to toggle source

Get the native function name given the emulated function name.

# File lib/sequel/dataset/sql.rb, line 1333
def native_function_name(emulated_function)
  self.class.const_get(:EMULATED_FUNCTION_MAP).fetch(emulated_function, emulated_function)
end
qualified_column_name(column, table) click to toggle source

Returns a qualified column name (including a table name) if the column name isn't already qualified.

# File lib/sequel/dataset/sql.rb, line 1339
def qualified_column_name(column, table)
  if column.is_a?(Symbol)
    c_table, column, _ = split_symbol(column)
    unless c_table
      case table
      when Symbol
        schema, table, t_alias = split_symbol(table)
        t_alias ||= Sequel::SQL::QualifiedIdentifier.new(schema, table) if schema
      when Sequel::SQL::AliasedExpression
        t_alias = table.alias
      end
      c_table = t_alias || table
    end
    ::Sequel::SQL::QualifiedIdentifier.new(c_table, column)
  else
    column
  end
end
qualified_expression(e, table) click to toggle source

Qualify the given expression e to the given table.

# File lib/sequel/dataset/sql.rb, line 1359
def qualified_expression(e, table)
  Qualifier.new(self, table).transform(e)
end
select_columns_sql(sql) click to toggle source
# File lib/sequel/dataset/sql.rb, line 1363
def select_columns_sql(sql)
  sql << SPACE
  column_list_append(sql, @opts[:select])
end
select_compounds_sql(sql) click to toggle source

Modify the sql to add a dataset to the via an EXCEPT, INTERSECT, or UNION clause. This uses a subselect for the compound datasets used, because using parantheses doesn't work on all databases. I consider this an ugly hack, but can't I think of a better default.

# File lib/sequel/dataset/sql.rb, line 1382
def select_compounds_sql(sql)
  return unless c = @opts[:compounds]
  c.each do |type, dataset, all|
    sql << SPACE << type.to_s.upcase
    sql << ALL if all
    sql << SPACE
    compound_dataset_sql_append(sql, dataset)
  end
end
select_distinct_sql(sql) click to toggle source
# File lib/sequel/dataset/sql.rb, line 1368
def select_distinct_sql(sql)
  if distinct = @opts[:distinct]
    sql << DISTINCT
    unless distinct.empty?
      sql << ON_PAREN
      expression_list_append(sql, distinct)
      sql << PAREN_CLOSE
    end
  end
end
select_from_sql(sql) click to toggle source
# File lib/sequel/dataset/sql.rb, line 1392
def select_from_sql(sql)
  if f = @opts[:from]
    sql << FROM
    source_list_append(sql, f)
  elsif f = empty_from_sql
    sql << f
  end
end
select_group_sql(sql) click to toggle source
# File lib/sequel/dataset/sql.rb, line 1401
def select_group_sql(sql)
  if group = @opts[:group]
    sql << GROUP_BY
    if go = @opts[:group_options]
      if go == :"grouping sets"
        sql << go.to_s.upcase << PAREN_OPEN
        grouping_element_list_append(sql, group)
        sql << PAREN_CLOSE
      elsif uses_with_rollup?
        expression_list_append(sql, group)
        sql << SPACE_WITH << go.to_s.upcase
      else
        sql << go.to_s.upcase << PAREN_OPEN
        expression_list_append(sql, group)
        sql << PAREN_CLOSE
      end
    else
      expression_list_append(sql, group)
    end
  end
end
select_having_sql(sql) click to toggle source
# File lib/sequel/dataset/sql.rb, line 1423
def select_having_sql(sql)
  if having = @opts[:having]
    sql << HAVING
    literal_append(sql, having)
  end
end
select_join_sql(sql) click to toggle source
# File lib/sequel/dataset/sql.rb, line 1430
def select_join_sql(sql)
  if js = @opts[:join]
    js.each{|j| literal_append(sql, j)}
  end
end
select_limit_sql(sql) click to toggle source
# File lib/sequel/dataset/sql.rb, line 1436
def select_limit_sql(sql)
  if l = @opts[:limit]
    sql << LIMIT
    literal_append(sql, l)
    if o = @opts[:offset]
      sql << OFFSET
      literal_append(sql, o)
    end
  elsif @opts[:offset]
    select_only_offset_sql(sql)
  end
end
select_lock_sql(sql) click to toggle source
# File lib/sequel/dataset/sql.rb, line 1449
def select_lock_sql(sql)
  case l = @opts[:lock]
  when :update
    sql << FOR_UPDATE
  when String
    sql << SPACE << l
  end
end
select_only_offset_sql(sql) click to toggle source

Used only if there is an offset and no limit, making it easier to override in the adapter, as many databases do not support just a plain offset with no limit.

# File lib/sequel/dataset/sql.rb, line 1461
def select_only_offset_sql(sql)
  sql << OFFSET
  literal_append(sql, @opts[:offset])
end
select_order_sql(sql) click to toggle source
# File lib/sequel/dataset/sql.rb, line 1466
def select_order_sql(sql)
  if o = @opts[:order]
    sql << ORDER_BY
    expression_list_append(sql, o)
  end
end
select_select_sql(sql) click to toggle source
# File lib/sequel/dataset/sql.rb, line 1475
def select_select_sql(sql)
  sql << SELECT
end
select_where_sql(sql) click to toggle source
# File lib/sequel/dataset/sql.rb, line 1479
def select_where_sql(sql)
  if w = @opts[:where]
    sql << WHERE
    literal_append(sql, w)
  end
end
select_with_sql(sql) click to toggle source
# File lib/sequel/dataset/sql.rb, line 1488
def select_with_sql(sql)
  return unless supports_cte?
  ws = opts[:with]
  return if !ws || ws.empty?
  sql << select_with_sql_base
  c = false
  comma = COMMA
  ws.each do |w|
    sql << comma if c
    quote_identifier_append(sql, w[:name])
    if args = w[:args]
     sql << PAREN_OPEN
     identifier_list_append(sql, args)
     sql << PAREN_CLOSE
    end
    sql << AS
    literal_dataset_append(sql, w[:dataset])
    c ||= true
  end
  sql << SPACE
end
select_with_sql_base() click to toggle source

The base keyword to use for the SQL WITH clause

# File lib/sequel/dataset/sql.rb, line 1514
def select_with_sql_base
  SQL_WITH
end
skip_symbol_cache?() click to toggle source

Whether the symbol cache should be skipped when literalizing the dataset

# File lib/sequel/dataset/sql.rb, line 1519
def skip_symbol_cache?
  @opts[:skip_symbol_cache]
end
source_list_append(sql, sources) click to toggle source

Append literalization of array of sources/tables to SQL string, raising an Error if there are no sources.

# File lib/sequel/dataset/sql.rb, line 1525
def source_list_append(sql, sources)
  raise(Error, 'No source specified for query') if sources.nil? || sources == []
  identifier_list_append(sql, sources)
end
split_symbol(sym) click to toggle source

Delegate to Sequel.split_symbol.

# File lib/sequel/dataset/sql.rb, line 1531
def split_symbol(sym)
  Sequel.split_symbol(sym)
end
sql_string_origin() click to toggle source

The string that is appended to to create the SQL query, the empty string by default

# File lib/sequel/dataset/sql.rb, line 1537
def sql_string_origin
  String.new
end
static_sql(sql) click to toggle source

SQL to use if this dataset uses static SQL. Since static SQL can be a PlaceholderLiteralString in addition to a String, we literalize nonstrings. If there is an append_sql for this dataset, append to that SQL instead of returning the value.

# File lib/sequel/dataset/sql.rb, line 1545
def static_sql(sql)
  if append_sql = @opts[:append_sql]
    if sql.is_a?(String)
      append_sql << sql
    else
      literal_append(append_sql, sql)
    end
  else
    if sql.is_a?(String)
      sql
    else
      literal(sql)
    end
  end
end
subselect_sql_append(sql, ds) click to toggle source

Append literalization of the subselect to SQL String.

# File lib/sequel/dataset/sql.rb, line 1562
def subselect_sql_append(sql, ds)
  ds.clone(:append_sql=>sql).sql
end
timestamp_precision() click to toggle source

The number of decimal digits of precision to use in timestamps.

# File lib/sequel/dataset/sql.rb, line 1567
def timestamp_precision
  supports_timestamp_usecs? ? 6 : 0
end
update_order_sql(sql)
Alias for: select_order_sql
update_returning_sql(sql)
update_set_sql(sql) click to toggle source
# File lib/sequel/dataset/sql.rb, line 1577
def update_set_sql(sql)
  sql << SET
  values = @opts[:values]
  if values.is_a?(Hash)
    update_sql_values_hash(sql, values)
  else
    sql << values
  end
end
update_sql_values_hash(sql, values) click to toggle source
# File lib/sequel/dataset/sql.rb, line 1587
def update_sql_values_hash(sql, values)
  c = false
  eq = EQUAL
  values.each do |k, v|
    sql << COMMA if c
    if k.is_a?(String) && !k.is_a?(LiteralString)
      quote_identifier_append(sql, k)
    else
      literal_append(sql, k)
    end
    sql << eq
    literal_append(sql, v)
    c ||= true
  end
end
update_table_sql(sql) click to toggle source
# File lib/sequel/dataset/sql.rb, line 1571
def update_table_sql(sql)
  sql << SPACE
  source_list_append(sql, @opts[:from])
  select_join_sql(sql) if supports_modifying_joins?
end
update_update_sql(sql) click to toggle source
# File lib/sequel/dataset/sql.rb, line 1603
def update_update_sql(sql)
  sql << UPDATE
end
update_where_sql(sql)
Alias for: select_where_sql
update_with_sql(sql)
Alias for: select_with_sql