module Sequel::Postgres::DatasetMethods

  1. lib/sequel/adapters/shared/postgres.rb

Constants

EXPLAIN_BOOLEAN_OPTIONS = {}  
EXPLAIN_NONBOOLEAN_OPTIONS = { :serialize => {:none=>"SERIALIZE NONE", :text=>"SERIALIZE TEXT", :binary=>"SERIALIZE BINARY"}.freeze, :format => {:text=>"FORMAT TEXT", :xml=>"FORMAT XML", :json=>"FORMAT JSON", :yaml=>"FORMAT YAML"}.freeze }.freeze  
LOCK_MODES = ['ACCESS SHARE', 'ROW SHARE', 'ROW EXCLUSIVE', 'SHARE UPDATE EXCLUSIVE', 'SHARE', 'SHARE ROW EXCLUSIVE', 'EXCLUSIVE', 'ACCESS EXCLUSIVE'].each(&:freeze).freeze  
NULL = LiteralString.new('NULL').freeze  

Public Instance methods

analyze()

Return the results of an EXPLAIN ANALYZE query as a string

[show source] 
     # File lib/sequel/adapters/shared/postgres.rb
1991 def analyze
1992   explain(:analyze=>true)
1993 end
complex_expression_sql_append(sql, op, args)

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

[show source] 
     # File lib/sequel/adapters/shared/postgres.rb
1998 def complex_expression_sql_append(sql, op, args)
1999   case op
2000   when :^
2001     j = ' # '
2002     c = false
2003     args.each do |a|
2004       sql << j if c
2005       literal_append(sql, a)
2006       c ||= true
2007     end
2008   when :ILIKE, :'NOT ILIKE'
2009     sql << '('
2010     literal_append(sql, args[0])
2011     sql << ' ' << op.to_s << ' '
2012     literal_append(sql, args[1])
2013     sql << ')'
2014   else
2015     super
2016   end
2017 end
disable_insert_returning()

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).

[show source] 
     # File lib/sequel/adapters/shared/postgres.rb
2033 def disable_insert_returning
2034   clone(:disable_insert_returning=>true)
2035 end
empty?()

Always return false when using VALUES

[show source] 
     # File lib/sequel/adapters/shared/postgres.rb
2038 def empty?
2039   return false if @opts[:values]
2040   super
2041 end
explain(opts=OPTS)

Return the results of an EXPLAIN query. Boolean options:

:analyze

Use the ANALYZE option.

:buffers

Use the BUFFERS option.

:costs

Use the COSTS option.

:generic_plan

Use the GENERIC_PLAN option.

:memory

Use the MEMORY option.

:settings

Use the SETTINGS option.

:summary

Use the SUMMARY option.

:timing

Use the TIMING option.

:verbose

Use the VERBOSE option.

:wal

Use the WAL option.

Non boolean options:

:format

Use the FORMAT option to change the format of the returned value. Values can be :text, :xml, :json, or :yaml.

:serialize

Use the SERIALIZE option to get timing on serialization. Values can be :none, :text, or :binary.

See the PostgreSQL EXPLAIN documentation for an explanation of what each option does.

In most cases, the return value is a single string. However, using the format: :json option can result in the return value being an array containing a hash.

[show source] 
     # File lib/sequel/adapters/shared/postgres.rb
2071 def explain(opts=OPTS)
2072   rows = clone(:append_sql=>explain_sql_string_origin(opts)).map(:'QUERY PLAN')
2073 
2074   if rows.length == 1
2075     rows[0]
2076   elsif rows.all?{|row| String === row}
2077     rows.join("\r\n") 
2078   # :nocov:
2079   else
2080     # This branch is unreachable in tests, but it seems better to just return
2081     # all rows than throw in error if this case actually happens.
2082     rows
2083   # :nocov:
2084   end
2085 end
for_key_share()

Return a cloned dataset which will use FOR KEY SHARE to lock returned rows. Supported on PostgreSQL 9.3+.

[show source] 
     # File lib/sequel/adapters/shared/postgres.rb
2089 def for_key_share
2090   cached_lock_style_dataset(:_for_key_share_ds, :key_share)
2091 end
for_no_key_update()

Return a cloned dataset which will use FOR NO KEY UPDATE to lock returned rows. This is generally a better choice than using for_update on PostgreSQL, unless you will be deleting the row or modifying a key column. Supported on PostgreSQL 9.3+.

[show source] 
     # File lib/sequel/adapters/shared/postgres.rb
2096 def for_no_key_update
2097   cached_lock_style_dataset(:_for_no_key_update_ds, :no_key_update)
2098 end
for_share()

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

[show source] 
     # File lib/sequel/adapters/shared/postgres.rb
2101 def for_share
2102   cached_lock_style_dataset(:_for_share_ds, :share)
2103 end
full_text_search(cols, terms, opts = OPTS)

Run a full text search on PostgreSQL. By default, searching for the inclusion of any of the terms in any of the cols.

Options:

:headline

Append a expression to the selected columns aliased to headline that contains an extract of the matched text.

:language

The language to use for the search (default: ‘simple’)

:plain

Whether a plain search should be used (default: false). In this case, terms should be a single string, and it will do a search where cols contains all of the words in terms. This ignores search operators in terms.

:phrase

Similar to :plain, but also adding an ILIKE filter to ensure that returned rows also include the exact phrase used.

:rank

Set to true to order by the rank, so that closer matches are returned first.

:to_tsquery

Can be set to :plain, :phrase, or :websearch to specify the function to use to convert the terms to a ts_query.

:tsquery

Specifies the terms argument is already a valid SQL expression returning a tsquery, and can be used directly in the query.

:tsvector

Specifies the cols argument is already a valid SQL expression returning a tsvector, and can be used directly in the query.

[show source] 
     # File lib/sequel/adapters/shared/postgres.rb
2124 def full_text_search(cols, terms, opts = OPTS)
2125   lang = Sequel.cast(opts[:language] || 'simple', :regconfig)
2126 
2127   unless opts[:tsvector]
2128     phrase_cols = full_text_string_join(cols)
2129     cols = Sequel.function(:to_tsvector, lang, phrase_cols)
2130   end
2131 
2132   unless opts[:tsquery]
2133     phrase_terms = terms.is_a?(Array) ? terms.join(' | ') : terms
2134 
2135     query_func = case to_tsquery = opts[:to_tsquery]
2136     when :phrase, :plain
2137       :"#{to_tsquery}to_tsquery"
2138     when :websearch
2139       :"websearch_to_tsquery"
2140     else
2141       (opts[:phrase] || opts[:plain]) ? :plainto_tsquery : :to_tsquery
2142     end
2143 
2144     terms = Sequel.function(query_func, lang, phrase_terms)
2145   end
2146 
2147   ds = where(Sequel.lit(["", " @@ ", ""], cols, terms))
2148 
2149   if opts[:phrase]
2150     raise Error, "can't use :phrase with either :tsvector or :tsquery arguments to full_text_search together" if opts[:tsvector] || opts[:tsquery]
2151     ds = ds.grep(phrase_cols, "%#{escape_like(phrase_terms)}%", :case_insensitive=>true)
2152   end
2153 
2154   if opts[:rank]
2155     ds = ds.reverse{ts_rank_cd(cols, terms)}
2156   end
2157 
2158   if opts[:headline]
2159     ds = ds.select_append{ts_headline(lang, phrase_cols, terms).as(:headline)}
2160   end
2161 
2162   ds
2163 end
insert(*values)

Insert given values into the database.

[show source] 
     # File lib/sequel/adapters/shared/postgres.rb
2166 def insert(*values)
2167   if @opts[:returning]
2168     # Already know which columns to return, let the standard code handle it
2169     super
2170   elsif @opts[:sql] || @opts[:disable_insert_returning]
2171     # Raw SQL used or RETURNING disabled, just use the default behavior
2172     # and return nil since sequence is not known.
2173     super
2174     nil
2175   else
2176     # Force the use of RETURNING with the primary key value,
2177     # unless it has been disabled.
2178     returning(insert_pk).insert(*values){|r| return r.values.first}
2179   end
2180 end
insert_conflict(opts=OPTS)

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: Sequel[: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: Sequel[:excluded][:b]}, update_where: {Sequel[: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)
[show source] 
     # File lib/sequel/adapters/shared/postgres.rb
2217 def insert_conflict(opts=OPTS)
2218   clone(:insert_conflict => opts)
2219 end
insert_ignore()

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
[show source] 
     # File lib/sequel/adapters/shared/postgres.rb
2227 def insert_ignore
2228   insert_conflict
2229 end
insert_select(*values)

Insert a record, returning the record inserted, using RETURNING. Always returns nil without running an INSERT statement if disable_insert_returning is used. If the query runs but returns no values, returns false.

[show source] 
     # File lib/sequel/adapters/shared/postgres.rb
2234 def insert_select(*values)
2235   return unless supports_insert_select?
2236   # Handle case where query does not return a row
2237   server?(:default).with_sql_first(insert_select_sql(*values)) || false
2238 end
insert_select_sql(*values)

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

[show source] 
     # File lib/sequel/adapters/shared/postgres.rb
2242 def insert_select_sql(*values)
2243   ds = opts[:returning] ? self : returning
2244   ds.insert_sql(*values)
2245 end
join_table(type, table, expr=nil, options=OPTS, &block)

Support SQL::AliasedExpression as expr to setup a USING join with a table alias for the USING columns.

[show source] 
     # File lib/sequel/adapters/shared/postgres.rb
2249 def join_table(type, table, expr=nil, options=OPTS, &block)
2250   if expr.is_a?(SQL::AliasedExpression) && expr.expression.is_a?(Array) && !expr.expression.empty? && expr.expression.all?
2251     options = options.merge(:join_using=>true)
2252   end
2253   super
2254 end
lock(mode, opts=OPTS)

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.

[show source] 
     # File lib/sequel/adapters/shared/postgres.rb
2261 def lock(mode, opts=OPTS)
2262   if defined?(yield) # perform locking inside a transaction and yield to block
2263     @db.transaction(opts){lock(mode, opts); yield}
2264   else
2265     sql = 'LOCK TABLE '.dup
2266     source_list_append(sql, @opts[:from])
2267     mode = mode.to_s.upcase.strip
2268     unless LOCK_MODES.include?(mode)
2269       raise Error, "Unsupported lock mode: #{mode}"
2270     end
2271     sql << " IN #{mode} MODE"
2272     @db.execute(sql, opts)
2273   end
2274   nil
2275 end
merge(&block)

Support MERGE RETURNING on PostgreSQL 17+.

[show source] 
     # File lib/sequel/adapters/shared/postgres.rb
2278 def merge(&block)
2279   sql = merge_sql
2280   if uses_returning?(:merge)
2281     returning_fetch_rows(sql, &block)
2282   else
2283     execute_ddl(sql)
2284   end
2285 end
merge_delete_when_not_matched_by_source(&block)

Return a dataset with a WHEN NOT MATCHED BY SOURCE THEN DELETE clause added to the MERGE statement. If a block is passed, treat it as a virtual row and use it as additional conditions for the match.

merge_delete_not_matched_by_source
# WHEN NOT MATCHED BY SOURCE THEN DELETE

merge_delete_not_matched_by_source{a > 30}
# WHEN NOT MATCHED BY SOURCE AND (a > 30) THEN DELETE
[show source] 
     # File lib/sequel/adapters/shared/postgres.rb
2296 def merge_delete_when_not_matched_by_source(&block)
2297   _merge_when(:type=>:delete_not_matched_by_source, &block)
2298 end
merge_do_nothing_when_matched(&block)

Return a dataset with a WHEN MATCHED THEN DO NOTHING clause added to the MERGE statement. If a block is passed, treat it as a virtual row and use it as additional conditions for the match.

merge_do_nothing_when_matched
# WHEN MATCHED THEN DO NOTHING

merge_do_nothing_when_matched{a > 30}
# WHEN MATCHED AND (a > 30) THEN DO NOTHING
[show source] 
     # File lib/sequel/adapters/shared/postgres.rb
2309 def merge_do_nothing_when_matched(&block)
2310   _merge_when(:type=>:matched, &block)
2311 end
merge_do_nothing_when_not_matched(&block)

Return a dataset with a WHEN NOT MATCHED THEN DO NOTHING clause added to the MERGE statement. If a block is passed, treat it as a virtual row and use it as additional conditions for the match.

merge_do_nothing_when_not_matched
# WHEN NOT MATCHED THEN DO NOTHING

merge_do_nothing_when_not_matched{a > 30}
# WHEN NOT MATCHED AND (a > 30) THEN DO NOTHING
[show source] 
     # File lib/sequel/adapters/shared/postgres.rb
2322 def merge_do_nothing_when_not_matched(&block)
2323   _merge_when(:type=>:not_matched, &block)
2324 end
merge_do_nothing_when_not_matched_by_source(&block)

Return a dataset with a WHEN NOT MATCHED BY SOURCE THEN DO NOTHING clause added to the MERGE BY SOURCE statement. If a block is passed, treat it as a virtual row and use it as additional conditions for the match.

merge_do_nothing_when_not_matched_by_source
# WHEN NOT MATCHED BY SOURCE THEN DO NOTHING

merge_do_nothing_when_not_matched_by_source{a > 30}
# WHEN NOT MATCHED BY SOURCE AND (a > 30) THEN DO NOTHING
[show source] 
     # File lib/sequel/adapters/shared/postgres.rb
2335 def merge_do_nothing_when_not_matched_by_source(&block)
2336   _merge_when(:type=>:not_matched_by_source, &block)
2337 end
merge_insert(*values, &block)

Support OVERRIDING USER|SYSTEM VALUE for MERGE INSERT.

[show source] 
     # File lib/sequel/adapters/shared/postgres.rb
2340 def merge_insert(*values, &block)
2341   h = {:type=>:insert, :values=>values}
2342   if @opts[:override]
2343     h[:override] = insert_override_sql(String.new)
2344   end
2345   _merge_when(h, &block)
2346 end
merge_update_when_not_matched_by_source(values, &block)

Return a dataset with a WHEN NOT MATCHED BY SOURCE THEN UPDATE clause added to the MERGE statement. If a block is passed, treat it as a virtual row and use it as additional conditions for the match.

merge_update_not_matched_by_source(i1: Sequel[:i1]+:i2+10, a: Sequel[:a]+:b+20)
# WHEN NOT MATCHED BY SOURCE THEN UPDATE SET i1 = (i1 + i2 + 10), a = (a + b + 20)

merge_update_not_matched_by_source(i1: :i2){a > 30}
# WHEN NOT MATCHED BY SOURCE AND (a > 30) THEN UPDATE SET i1 = i2
[show source] 
     # File lib/sequel/adapters/shared/postgres.rb
2357 def merge_update_when_not_matched_by_source(values, &block)
2358   _merge_when(:type=>:update_not_matched_by_source, :values=>values, &block)
2359 end
overriding_system_value()

Use OVERRIDING USER VALUE for INSERT statements, so that identity columns always use the user supplied value, and an error is not raised for identity columns that are GENERATED ALWAYS.

[show source] 
     # File lib/sequel/adapters/shared/postgres.rb
2364 def overriding_system_value
2365   clone(:override=>:system)
2366 end
overriding_user_value()

Use OVERRIDING USER VALUE for INSERT statements, so that identity columns always use the sequence value instead of the user supplied value.

[show source] 
     # File lib/sequel/adapters/shared/postgres.rb
2370 def overriding_user_value
2371   clone(:override=>:user)
2372 end
supports_cte?(type=:select)
[show source] 
     # File lib/sequel/adapters/shared/postgres.rb
2374 def supports_cte?(type=:select)
2375   if type == :select
2376     server_version >= 80400
2377   else
2378     server_version >= 90100
2379   end
2380 end
supports_cte_in_subqueries?()

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

[show source] 
     # File lib/sequel/adapters/shared/postgres.rb
2384 def supports_cte_in_subqueries?
2385   supports_cte?
2386 end
supports_distinct_on?()

DISTINCT ON is a PostgreSQL extension

[show source] 
     # File lib/sequel/adapters/shared/postgres.rb
2389 def supports_distinct_on?
2390   true
2391 end
supports_group_cube?()

PostgreSQL 9.5+ supports GROUP CUBE

[show source] 
     # File lib/sequel/adapters/shared/postgres.rb
2394 def supports_group_cube?
2395   server_version >= 90500
2396 end
supports_group_rollup?()

PostgreSQL 9.5+ supports GROUP ROLLUP

[show source] 
     # File lib/sequel/adapters/shared/postgres.rb
2399 def supports_group_rollup?
2400   server_version >= 90500
2401 end
supports_grouping_sets?()

PostgreSQL 9.5+ supports GROUPING SETS

[show source] 
     # File lib/sequel/adapters/shared/postgres.rb
2404 def supports_grouping_sets?
2405   server_version >= 90500
2406 end
supports_insert_conflict?()

PostgreSQL 9.5+ supports the ON CONFLICT clause to INSERT.

[show source] 
     # File lib/sequel/adapters/shared/postgres.rb
2414 def supports_insert_conflict?
2415   server_version >= 90500
2416 end
supports_insert_select?()

True unless insert returning has been disabled for this dataset.

[show source] 
     # File lib/sequel/adapters/shared/postgres.rb
2409 def supports_insert_select?
2410   !@opts[:disable_insert_returning]
2411 end
supports_lateral_subqueries?()

PostgreSQL 9.3+ supports lateral subqueries

[show source] 
     # File lib/sequel/adapters/shared/postgres.rb
2419 def supports_lateral_subqueries?
2420   server_version >= 90300
2421 end
supports_merge?()

PostgreSQL 15+ supports MERGE.

[show source] 
     # File lib/sequel/adapters/shared/postgres.rb
2429 def supports_merge?
2430   server_version >= 150000
2431 end
supports_modifying_joins?()

PostgreSQL supports modifying joined datasets

[show source] 
     # File lib/sequel/adapters/shared/postgres.rb
2424 def supports_modifying_joins?
2425   true
2426 end
supports_nowait?()

PostgreSQL supports NOWAIT.

[show source] 
     # File lib/sequel/adapters/shared/postgres.rb
2434 def supports_nowait?
2435   true
2436 end
supports_regexp?()

PostgreSQL supports pattern matching via regular expressions

[show source] 
     # File lib/sequel/adapters/shared/postgres.rb
2449 def supports_regexp?
2450   true
2451 end
supports_returning?(type)

MERGE RETURNING is supported on PostgreSQL 17+. Other RETURNING is supported on all supported PostgreSQL versions.

[show source] 
     # File lib/sequel/adapters/shared/postgres.rb
2440 def supports_returning?(type)
2441   if type == :merge
2442     server_version >= 170000
2443   else
2444     true
2445   end
2446 end
supports_skip_locked?()

PostgreSQL 9.5+ supports SKIP LOCKED.

[show source] 
     # File lib/sequel/adapters/shared/postgres.rb
2454 def supports_skip_locked?
2455   server_version >= 90500
2456 end
supports_timestamp_timezones?()

PostgreSQL supports timezones in literal timestamps

[show source] 
     # File lib/sequel/adapters/shared/postgres.rb
2461 def supports_timestamp_timezones?
2462   # SEQUEL6: Remove
2463   true
2464 end
supports_window_clause?()

PostgreSQL 8.4+ supports WINDOW clause.

[show source] 
     # File lib/sequel/adapters/shared/postgres.rb
2468 def supports_window_clause?
2469   server_version >= 80400
2470 end
supports_window_function_frame_option?(option)

Base support added in 8.4, offset supported added in 9.0, GROUPS and EXCLUDE support added in 11.0.

[show source] 
     # File lib/sequel/adapters/shared/postgres.rb
2479 def supports_window_function_frame_option?(option)
2480   case option
2481   when :rows, :range
2482     true
2483   when :offset
2484     server_version >= 90000
2485   when :groups, :exclude
2486     server_version >= 110000
2487   else
2488     false
2489   end
2490 end
supports_window_functions?()

PostgreSQL 8.4+ supports window functions

[show source] 
     # File lib/sequel/adapters/shared/postgres.rb
2473 def supports_window_functions?
2474   server_version >= 80400
2475 end
truncate(opts = OPTS)

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"

DB[:table].truncate(cascade: true, only: true, restart: true)
# TRUNCATE TABLE ONLY "table" RESTART IDENTITY CASCADE
[show source] 
     # File lib/sequel/adapters/shared/postgres.rb
2508 def truncate(opts = OPTS)
2509   if opts.empty?
2510     super()
2511   else
2512     clone(:truncate_opts=>opts).truncate
2513   end
2514 end
with_ties()

Use WITH TIES when limiting the result set to also include additional rules that have the same results for the order column as the final row. Requires PostgreSQL 13.

[show source] 
     # File lib/sequel/adapters/shared/postgres.rb
2519 def with_ties
2520   clone(:limit_with_ties=>true)
2521 end

Protected Instance methods

_import(columns, values, opts=OPTS)

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.

[show source] 
     # File lib/sequel/adapters/shared/postgres.rb
2529 def _import(columns, values, opts=OPTS)
2530   if @opts[:returning]
2531     # no transaction: our multi_insert_sql_strategy should guarantee
2532     # that there's only ever a single statement.
2533     sql = multi_insert_sql(columns, values)[0]
2534     returning_fetch_rows(sql).map{|v| v.length == 1 ? v.values.first : v}
2535   elsif opts[:return] == :primary_key
2536     returning(insert_pk)._import(columns, values, opts)
2537   else
2538     super
2539   end
2540 end
to_prepared_statement(type, *a)
[show source] 
     # File lib/sequel/adapters/shared/postgres.rb
2542 def to_prepared_statement(type, *a)
2543   if type == :insert && !@opts.has_key?(:returning)
2544     returning(insert_pk).send(:to_prepared_statement, :insert_pk, *a)
2545   else
2546     super
2547   end
2548 end