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
2000 def analyze
2001   explain(:analyze=>true)
2002 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
2007 def complex_expression_sql_append(sql, op, args)
2008   case op
2009   when :^
2010     j = ' # '
2011     c = false
2012     args.each do |a|
2013       sql << j if c
2014       literal_append(sql, a)
2015       c ||= true
2016     end
2017   when :ILIKE, :'NOT ILIKE'
2018     sql << '('
2019     literal_append(sql, args[0])
2020     sql << ' ' << op.to_s << ' '
2021     literal_append(sql, args[1])
2022     sql << ')'
2023   else
2024     super
2025   end
2026 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
2042 def disable_insert_returning
2043   clone(:disable_insert_returning=>true)
2044 end
empty?()

Always return false when using VALUES

[show source] 
     # File lib/sequel/adapters/shared/postgres.rb
2047 def empty?
2048   return false if @opts[:values]
2049   super
2050 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
2080 def explain(opts=OPTS)
2081   rows = clone(:append_sql=>explain_sql_string_origin(opts)).map(:'QUERY PLAN')
2082 
2083   if rows.length == 1
2084     rows[0]
2085   elsif rows.all?{|row| String === row}
2086     rows.join("\r\n") 
2087   # :nocov:
2088   else
2089     # This branch is unreachable in tests, but it seems better to just return
2090     # all rows than throw in error if this case actually happens.
2091     rows
2092   # :nocov:
2093   end
2094 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
2098 def for_key_share
2099   cached_lock_style_dataset(:_for_key_share_ds, :key_share)
2100 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
2105 def for_no_key_update
2106   cached_lock_style_dataset(:_for_no_key_update_ds, :no_key_update)
2107 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
2110 def for_share
2111   cached_lock_style_dataset(:_for_share_ds, :share)
2112 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
2133 def full_text_search(cols, terms, opts = OPTS)
2134   lang = Sequel.cast(opts[:language] || 'simple', :regconfig)
2135 
2136   unless opts[:tsvector]
2137     phrase_cols = full_text_string_join(cols)
2138     cols = Sequel.function(:to_tsvector, lang, phrase_cols)
2139   end
2140 
2141   unless opts[:tsquery]
2142     phrase_terms = terms.is_a?(Array) ? terms.join(' | ') : terms
2143 
2144     query_func = case to_tsquery = opts[:to_tsquery]
2145     when :phrase, :plain
2146       :"#{to_tsquery}to_tsquery"
2147     when :websearch
2148       :"websearch_to_tsquery"
2149     else
2150       (opts[:phrase] || opts[:plain]) ? :plainto_tsquery : :to_tsquery
2151     end
2152 
2153     terms = Sequel.function(query_func, lang, phrase_terms)
2154   end
2155 
2156   ds = where(Sequel.lit(["", " @@ ", ""], cols, terms))
2157 
2158   if opts[:phrase]
2159     raise Error, "can't use :phrase with either :tsvector or :tsquery arguments to full_text_search together" if opts[:tsvector] || opts[:tsquery]
2160     ds = ds.grep(phrase_cols, "%#{escape_like(phrase_terms)}%", :case_insensitive=>true)
2161   end
2162 
2163   if opts[:rank]
2164     ds = ds.reverse{ts_rank_cd(cols, terms)}
2165   end
2166 
2167   if opts[:headline]
2168     ds = ds.select_append{ts_headline(lang, phrase_cols, terms).as(:headline)}
2169   end
2170 
2171   ds
2172 end
insert(*values)

Insert given values into the database.

[show source] 
     # File lib/sequel/adapters/shared/postgres.rb
2175 def insert(*values)
2176   if @opts[:returning]
2177     # Already know which columns to return, let the standard code handle it
2178     super
2179   elsif @opts[:sql] || @opts[:disable_insert_returning]
2180     # Raw SQL used or RETURNING disabled, just use the default behavior
2181     # and return nil since sequence is not known.
2182     super
2183     nil
2184   else
2185     # Force the use of RETURNING with the primary key value,
2186     # unless it has been disabled.
2187     returning(insert_pk).insert(*values){|r| return r.values.first}
2188   end
2189 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
2226 def insert_conflict(opts=OPTS)
2227   clone(:insert_conflict => opts)
2228 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
2236 def insert_ignore
2237   insert_conflict
2238 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
2243 def insert_select(*values)
2244   return unless supports_insert_select?
2245   # Handle case where query does not return a row
2246   server?(:default).with_sql_first(insert_select_sql(*values)) || false
2247 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
2251 def insert_select_sql(*values)
2252   ds = opts[:returning] ? self : returning
2253   ds.insert_sql(*values)
2254 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
2258 def join_table(type, table, expr=nil, options=OPTS, &block)
2259   if expr.is_a?(SQL::AliasedExpression) && expr.expression.is_a?(Array) && !expr.expression.empty? && expr.expression.all?
2260     options = options.merge(:join_using=>true)
2261   end
2262   super
2263 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
2270 def lock(mode, opts=OPTS)
2271   if defined?(yield) # perform locking inside a transaction and yield to block
2272     @db.transaction(opts){lock(mode, opts); yield}
2273   else
2274     sql = 'LOCK TABLE '.dup
2275     source_list_append(sql, @opts[:from])
2276     mode = mode.to_s.upcase.strip
2277     unless LOCK_MODES.include?(mode)
2278       raise Error, "Unsupported lock mode: #{mode}"
2279     end
2280     sql << " IN #{mode} MODE"
2281     @db.execute(sql, opts)
2282   end
2283   nil
2284 end
merge(&block)

Support MERGE RETURNING on PostgreSQL 17+.

[show source] 
     # File lib/sequel/adapters/shared/postgres.rb
2287 def merge(&block)
2288   sql = merge_sql
2289   if uses_returning?(:merge)
2290     returning_fetch_rows(sql, &block)
2291   else
2292     execute_ddl(sql)
2293   end
2294 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
2305 def merge_delete_when_not_matched_by_source(&block)
2306   _merge_when(:type=>:delete_not_matched_by_source, &block)
2307 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
2318 def merge_do_nothing_when_matched(&block)
2319   _merge_when(:type=>:matched, &block)
2320 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
2331 def merge_do_nothing_when_not_matched(&block)
2332   _merge_when(:type=>:not_matched, &block)
2333 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
2344 def merge_do_nothing_when_not_matched_by_source(&block)
2345   _merge_when(:type=>:not_matched_by_source, &block)
2346 end
merge_insert(*values, &block)

Support OVERRIDING USER|SYSTEM VALUE for MERGE INSERT.

[show source] 
     # File lib/sequel/adapters/shared/postgres.rb
2349 def merge_insert(*values, &block)
2350   h = {:type=>:insert, :values=>values}
2351   if @opts[:override]
2352     h[:override] = insert_override_sql(String.new)
2353   end
2354   _merge_when(h, &block)
2355 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
2366 def merge_update_when_not_matched_by_source(values, &block)
2367   _merge_when(:type=>:update_not_matched_by_source, :values=>values, &block)
2368 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
2373 def overriding_system_value
2374   clone(:override=>:system)
2375 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
2379 def overriding_user_value
2380   clone(:override=>:user)
2381 end
supports_cte?(type=:select)
[show source] 
     # File lib/sequel/adapters/shared/postgres.rb
2383 def supports_cte?(type=:select)
2384   if type == :select
2385     server_version >= 80400
2386   else
2387     server_version >= 90100
2388   end
2389 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
2393 def supports_cte_in_subqueries?
2394   supports_cte?
2395 end
supports_distinct_on?()

DISTINCT ON is a PostgreSQL extension

[show source] 
     # File lib/sequel/adapters/shared/postgres.rb
2398 def supports_distinct_on?
2399   true
2400 end
supports_group_cube?()

PostgreSQL 9.5+ supports GROUP CUBE

[show source] 
     # File lib/sequel/adapters/shared/postgres.rb
2403 def supports_group_cube?
2404   server_version >= 90500
2405 end
supports_group_rollup?()

PostgreSQL 9.5+ supports GROUP ROLLUP

[show source] 
     # File lib/sequel/adapters/shared/postgres.rb
2408 def supports_group_rollup?
2409   server_version >= 90500
2410 end
supports_grouping_sets?()

PostgreSQL 9.5+ supports GROUPING SETS

[show source] 
     # File lib/sequel/adapters/shared/postgres.rb
2413 def supports_grouping_sets?
2414   server_version >= 90500
2415 end
supports_insert_conflict?()

PostgreSQL 9.5+ supports the ON CONFLICT clause to INSERT.

[show source] 
     # File lib/sequel/adapters/shared/postgres.rb
2423 def supports_insert_conflict?
2424   server_version >= 90500
2425 end
supports_insert_select?()

True unless insert returning has been disabled for this dataset.

[show source] 
     # File lib/sequel/adapters/shared/postgres.rb
2418 def supports_insert_select?
2419   !@opts[:disable_insert_returning]
2420 end
supports_lateral_subqueries?()

PostgreSQL 9.3+ supports lateral subqueries

[show source] 
     # File lib/sequel/adapters/shared/postgres.rb
2428 def supports_lateral_subqueries?
2429   server_version >= 90300
2430 end
supports_merge?()

PostgreSQL 15+ supports MERGE.

[show source] 
     # File lib/sequel/adapters/shared/postgres.rb
2438 def supports_merge?
2439   server_version >= 150000
2440 end
supports_modifying_joins?()

PostgreSQL supports modifying joined datasets

[show source] 
     # File lib/sequel/adapters/shared/postgres.rb
2433 def supports_modifying_joins?
2434   true
2435 end
supports_nowait?()

PostgreSQL supports NOWAIT.

[show source] 
     # File lib/sequel/adapters/shared/postgres.rb
2443 def supports_nowait?
2444   true
2445 end
supports_regexp?()

PostgreSQL supports pattern matching via regular expressions

[show source] 
     # File lib/sequel/adapters/shared/postgres.rb
2458 def supports_regexp?
2459   true
2460 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
2449 def supports_returning?(type)
2450   if type == :merge
2451     server_version >= 170000
2452   else
2453     true
2454   end
2455 end
supports_skip_locked?()

PostgreSQL 9.5+ supports SKIP LOCKED.

[show source] 
     # File lib/sequel/adapters/shared/postgres.rb
2463 def supports_skip_locked?
2464   server_version >= 90500
2465 end
supports_timestamp_timezones?()

PostgreSQL supports timezones in literal timestamps

[show source] 
     # File lib/sequel/adapters/shared/postgres.rb
2470 def supports_timestamp_timezones?
2471   # SEQUEL6: Remove
2472   true
2473 end
supports_window_clause?()

PostgreSQL 8.4+ supports WINDOW clause.

[show source] 
     # File lib/sequel/adapters/shared/postgres.rb
2477 def supports_window_clause?
2478   server_version >= 80400
2479 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
2488 def supports_window_function_frame_option?(option)
2489   case option
2490   when :rows, :range
2491     true
2492   when :offset
2493     server_version >= 90000
2494   when :groups, :exclude
2495     server_version >= 110000
2496   else
2497     false
2498   end
2499 end
supports_window_functions?()

PostgreSQL 8.4+ supports window functions

[show source] 
     # File lib/sequel/adapters/shared/postgres.rb
2482 def supports_window_functions?
2483   server_version >= 80400
2484 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
2517 def truncate(opts = OPTS)
2518   if opts.empty?
2519     super()
2520   else
2521     clone(:truncate_opts=>opts).truncate
2522   end
2523 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
2528 def with_ties
2529   clone(:limit_with_ties=>true)
2530 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
2538 def _import(columns, values, opts=OPTS)
2539   if @opts[:returning]
2540     # no transaction: our multi_insert_sql_strategy should guarantee
2541     # that there's only ever a single statement.
2542     sql = multi_insert_sql(columns, values)[0]
2543     returning_fetch_rows(sql).map{|v| v.length == 1 ? v.values.first : v}
2544   elsif opts[:return] == :primary_key
2545     returning(insert_pk)._import(columns, values, opts)
2546   else
2547     super
2548   end
2549 end
to_prepared_statement(type, *a)
[show source] 
     # File lib/sequel/adapters/shared/postgres.rb
2551 def to_prepared_statement(type, *a)
2552   if type == :insert && !@opts.has_key?(:returning)
2553     returning(insert_pk).send(:to_prepared_statement, :insert_pk, *a)
2554   else
2555     super
2556   end
2557 end