module Sequel::Postgres::DatasetMethods

Instance methods for datasets that connect to a PostgreSQL database.

Constants

ACCESS_EXCLUSIVE
ACCESS_SHARE
APOS
APOS_RE
AS
BACKSLASH
BLOB_RE
BOOL_FALSE
BOOL_TRUE
COMMA
COMMA_SEPARATOR
CRLF
DOUBLE_APOS
EMPTY_STRING
ESCAPE
EXCLUSIVE
EXPLAIN
EXPLAIN_ANALYZE
FOR_SHARE
FROM
LOCK_MODES
NON_SQL_OPTIONS
NULL
PAREN_CLOSE
PAREN_OPEN
PG_TIMESTAMP_FORMAT
QUERY_PLAN
ROW_EXCLUSIVE
ROW_SHARE
SELECT_VALUES
SHARE
SHARE_ROW_EXCLUSIVE
SHARE_UPDATE_EXCLUSIVE
SKIP_LOCKED
SPACE
SQL_WITH_RECURSIVE
WINDOW
XOR_OP

Public Instance Methods

analyze() click to toggle source

Return the results of an EXPLAIN ANALYZE query as a string

# File lib/sequel/adapters/shared/postgres.rb, line 1319
def analyze
  explain(:analyze=>true)
end
complex_expression_sql_append(sql, op, args) click to toggle source

Handle converting the ruby xor operator (^) into the PostgreSQL xor operator (#), and use the ILIKE and NOT ILIKE operators.

# File lib/sequel/adapters/shared/postgres.rb, line 1326
def complex_expression_sql_append(sql, op, args)
  case op
  when :^
    j = ' # '
    c = false
    args.each do |a|
      sql << j if c
      literal_append(sql, a)
      c ||= true
    end
  when :ILIKE, :'NOT ILIKE'
    sql << '('
    literal_append(sql, args[0])
    sql << ' ' << op.to_s << ' '
    literal_append(sql, args[1])
    sql << " ESCAPE "
    literal_append(sql, "\\")
    sql << ')'
  else
    super
  end
end
disable_insert_returning() click to toggle source

Disables automatic use of INSERT … RETURNING. You can still use returning manually to force the use of RETURNING when inserting.

This is designed for cases where INSERT RETURNING cannot be used, such as when you are using partitioning with trigger functions or conditional rules, or when you are using a PostgreSQL version less than 8.2, or a PostgreSQL derivative that does not support returning.

Note that when this method is used, insert will not return the primary key of the inserted row, you will have to get the primary key of the inserted row before inserting via nextval, or after inserting via currval or lastval (making sure to use the same database connection for currval or lastval).

# File lib/sequel/adapters/shared/postgres.rb, line 1363
def disable_insert_returning
  clone(:disable_insert_returning=>true)
end
explain(opts=OPTS) click to toggle source

Return the results of an EXPLAIN query as a string

# File lib/sequel/adapters/shared/postgres.rb, line 1368
def explain(opts=OPTS)
  with_sql((opts[:analyze] ? 'EXPLAIN ANALYZE ' : 'EXPLAIN ') + select_sql).map(:'QUERY PLAN').join("\r\n")
end
for_share() click to toggle source

Return a cloned dataset which will use FOR SHARE to lock returned rows.

# File lib/sequel/adapters/shared/postgres.rb, line 1373
def for_share
  lock_style(:share)
end
insert(*values) click to toggle source

Insert given values into the database.

# File lib/sequel/adapters/shared/postgres.rb, line 1436
def insert(*values)
  if @opts[:returning]
    # Already know which columns to return, let the standard code handle it
    super
  elsif @opts[:sql] || @opts[:disable_insert_returning]
    # Raw SQL used or RETURNING disabled, just use the default behavior
    # and return nil since sequence is not known.
    super
    nil
  else
    # Force the use of RETURNING with the primary key value,
    # unless it has been disabled.
    returning(insert_pk).insert(*values){|r| return r.values.first}
  end
end
insert_conflict(opts=OPTS) click to toggle source

Handle uniqueness violations when inserting, by updating the conflicting row, using ON CONFLICT. With no options, uses ON CONFLICT DO NOTHING. Options:

:conflict_where

The index filter, when using a partial index to determine uniqueness.

:constraint

An explicit constraint name, has precendence over :target.

:target

The column name or expression to handle uniqueness violations on.

:update

A hash of columns and values to set. Uses ON CONFLICT DO UPDATE.

:update_where

A WHERE condition to use for the update.

Examples:

DB[:table].insert_conflict.insert(:a=>1, :b=>2)
# INSERT INTO TABLE (a, b) VALUES (1, 2)
# ON CONFLICT DO NOTHING

DB[:table].insert_conflict(:constraint=>:table_a_uidx).insert(:a=>1, :b=>2)
# INSERT INTO TABLE (a, b) VALUES (1, 2)
# ON CONFLICT ON CONSTRAINT table_a_uidx DO NOTHING

DB[:table].insert_conflict(:target=>:a).insert(:a=>1, :b=>2)
# INSERT INTO TABLE (a, b) VALUES (1, 2)
# ON CONFLICT (a) DO NOTHING

DB[:table].insert_conflict(:target=>:a, :conflict_where=>{:c=>true}).insert(:a=>1, :b=>2)
# INSERT INTO TABLE (a, b) VALUES (1, 2)
# ON CONFLICT (a) WHERE (c IS TRUE) DO NOTHING

DB[:table].insert_conflict(:target=>:a, :update=>{:b=>:excluded__b}).insert(:a=>1, :b=>2)
# INSERT INTO TABLE (a, b) VALUES (1, 2)
# ON CONFLICT (a) DO UPDATE SET b = excluded.b

DB[:table].insert_conflict(:constraint=>:table_a_uidx,
  :update=>{:b=>:excluded__b}, :update_where=>{:table__status_id=>1}).insert(:a=>1, :b=>2)
# INSERT INTO TABLE (a, b) VALUES (1, 2)
# ON CONFLICT ON CONSTRAINT table_a_uidx
# DO UPDATE SET b = excluded.b WHERE (table.status_id = 1)
# File lib/sequel/adapters/shared/postgres.rb, line 1487
def insert_conflict(opts=OPTS)
  clone(:insert_conflict => opts)
end
insert_ignore() click to toggle source

Ignore uniqueness/exclusion violations when inserting, using ON CONFLICT DO NOTHING. Exists mostly for compatibility to MySQL’s insert_ignore. Example:

DB[:table].insert_ignore.insert(:a=>1, :b=>2)
# INSERT INTO TABLE (a, b) VALUES (1, 2)
# ON CONFLICT DO NOTHING
# File lib/sequel/adapters/shared/postgres.rb, line 1497
def insert_ignore
  insert_conflict
end
insert_select(*values) click to toggle source

Insert a record returning the record inserted. Always returns nil without inserting a query if #disable_insert_returning is used.

# File lib/sequel/adapters/shared/postgres.rb, line 1503
def insert_select(*values)
  return unless supports_insert_select?
  server?(:default).with_sql_first(insert_select_sql(*values))
end
insert_select_sql(*values) click to toggle source

The SQL to use for an #insert_select, adds a RETURNING clause to the insert unless the RETURNING clause is already present.

# File lib/sequel/adapters/shared/postgres.rb, line 1510
def insert_select_sql(*values)
  ds = opts[:returning] ? self : returning
  ds.insert_sql(*values)
end
lock(mode, opts=OPTS) { || ... } click to toggle source

Locks all tables in the dataset’s FROM clause (but not in JOINs) with the specified mode (e.g. ‘EXCLUSIVE’). If a block is given, starts a new transaction, locks the table, and yields. If a block is not given just locks the tables. Note that PostgreSQL will probably raise an error if you lock the table outside of an existing transaction. Returns nil.

# File lib/sequel/adapters/shared/postgres.rb, line 1520
def lock(mode, opts=OPTS)
  if block_given? # perform locking inside a transaction and yield to block
    @db.transaction(opts){lock(mode, opts); yield}
  else
    sql = 'LOCK TABLE '.dup
    source_list_append(sql, @opts[:from])
    mode = mode.to_s.upcase.strip
    unless LOCK_MODES.include?(mode)
      raise Error, "Unsupported lock mode: #{mode}"
    end
    sql << " IN #{mode} MODE"
    @db.execute(sql, opts)
  end
  nil
end
supports_cte?(type=:select) click to toggle source
# File lib/sequel/adapters/shared/postgres.rb, line 1536
def supports_cte?(type=:select)
  if type == :select
    server_version >= 80400
  else
    server_version >= 90100
  end
end
supports_cte_in_subqueries?() click to toggle source

PostgreSQL supports using the WITH clause in subqueries if it supports using WITH at all (i.e. on PostgreSQL 8.4+).

# File lib/sequel/adapters/shared/postgres.rb, line 1546
def supports_cte_in_subqueries?
  supports_cte?
end
supports_distinct_on?() click to toggle source

DISTINCT ON is a PostgreSQL extension

# File lib/sequel/adapters/shared/postgres.rb, line 1551
def supports_distinct_on?
  true
end
supports_group_cube?() click to toggle source

PostgreSQL 9.5+ supports GROUP CUBE

# File lib/sequel/adapters/shared/postgres.rb, line 1556
def supports_group_cube?
  server_version >= 90500
end
supports_group_rollup?() click to toggle source

PostgreSQL 9.5+ supports GROUP ROLLUP

# File lib/sequel/adapters/shared/postgres.rb, line 1561
def supports_group_rollup?
  server_version >= 90500
end
supports_grouping_sets?() click to toggle source

PostgreSQL 9.5+ supports GROUPING SETS

# File lib/sequel/adapters/shared/postgres.rb, line 1566
def supports_grouping_sets?
  server_version >= 90500
end
supports_insert_conflict?() click to toggle source

PostgreSQL 9.5+ supports the ON CONFLICT clause to INSERT.

# File lib/sequel/adapters/shared/postgres.rb, line 1576
def supports_insert_conflict?
  server_version >= 90500
end
supports_insert_select?() click to toggle source

True unless insert returning has been disabled for this dataset.

# File lib/sequel/adapters/shared/postgres.rb, line 1571
def supports_insert_select?
  !@opts[:disable_insert_returning]
end
supports_lateral_subqueries?() click to toggle source

PostgreSQL 9.3rc1+ supports lateral subqueries

# File lib/sequel/adapters/shared/postgres.rb, line 1581
def supports_lateral_subqueries?
  server_version >= 90300
end
supports_modifying_joins?() click to toggle source

PostgreSQL supports modifying joined datasets

# File lib/sequel/adapters/shared/postgres.rb, line 1586
def supports_modifying_joins?
  true
end
supports_regexp?() click to toggle source

PostgreSQL supports pattern matching via regular expressions

# File lib/sequel/adapters/shared/postgres.rb, line 1596
def supports_regexp?
  true
end
supports_returning?(type) click to toggle source

Returning is always supported.

# File lib/sequel/adapters/shared/postgres.rb, line 1591
def supports_returning?(type)
  true
end
supports_skip_locked?() click to toggle source

PostgreSQL 9.5+ supports SKIP LOCKED.

# File lib/sequel/adapters/shared/postgres.rb, line 1601
def supports_skip_locked?
  server_version >= 90500
end
supports_timestamp_timezones?() click to toggle source

PostgreSQL supports timezones in literal timestamps

# File lib/sequel/adapters/shared/postgres.rb, line 1606
def supports_timestamp_timezones?
  true
end
supports_window_functions?() click to toggle source

PostgreSQL 8.4+ supports window functions

# File lib/sequel/adapters/shared/postgres.rb, line 1611
def supports_window_functions?
  server_version >= 80400
end
truncate(opts = OPTS) click to toggle source

Truncates the dataset. Returns nil.

Options:

:cascade

whether to use the CASCADE option, useful when truncating tables with foreign keys.

:only

truncate using ONLY, so child tables are unaffected

:restart

use RESTART IDENTITY to restart any related sequences

:only and :restart only work correctly on PostgreSQL 8.4+.

Usage:

DB[:table].truncate # TRUNCATE TABLE "table"
# => nil
DB[:table].truncate(:cascade => true, :only=>true, :restart=>true) # TRUNCATE TABLE ONLY "table" RESTART IDENTITY CASCADE
# => nil
# File lib/sequel/adapters/shared/postgres.rb, line 1630
def truncate(opts = OPTS)
  if opts.empty?
    super()
  else
    clone(:truncate_opts=>opts).truncate
  end
end
window(name, opts) click to toggle source

Return a clone of the dataset with an addition named window that can be referenced in window functions. See {SQL::Window} for a list of options that can be passed in.

# File lib/sequel/adapters/shared/postgres.rb, line 1641
def window(name, opts)
  clone(:window=>(@opts[:window]||[]) + [[name, SQL::Window.new(opts)]])
end

Protected Instance Methods

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

If returned primary keys are requested, use RETURNING unless already set on the dataset. If RETURNING is already set, use existing returning values. If RETURNING is only set to return a single columns, return an array of just that column. Otherwise, return an array of hashes.

# File lib/sequel/adapters/shared/postgres.rb, line 1651
def _import(columns, values, opts=OPTS)
  if @opts[:returning]
    statements = multi_insert_sql(columns, values)
    @db.transaction(Hash[opts].merge!(:server=>@opts[:server])) do
      statements.map{|st| returning_fetch_rows(st)}
    end.first.map{|v| v.length == 1 ? v.values.first : v}
  elsif opts[:return] == :primary_key
    returning(insert_pk)._import(columns, values, opts)
  else
    super
  end
end