Module: Sequel::Postgres::DatasetMethods

Includes:
UnmodifiedIdentifiers::DatasetMethods
Included in:
JDBC::Postgres::Dataset, Dataset
Defined in:
lib/sequel/adapters/shared/postgres.rb

Constant Summary collapse

NULL =
LiteralString.new('NULL').freeze
LOCK_MODES =
['ACCESS SHARE', 'ROW SHARE', 'ROW EXCLUSIVE', 'SHARE UPDATE EXCLUSIVE', 'SHARE', 'SHARE ROW EXCLUSIVE', 'EXCLUSIVE', 'ACCESS EXCLUSIVE'].each(&:freeze).freeze

Instance Method Summary collapse

Instance Method Details

#analyzeObject

Return the results of an EXPLAIN ANALYZE query as a string


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# File 'lib/sequel/adapters/shared/postgres.rb', line 1532

def analyze
  explain(:analyze=>true)
end

#complex_expression_sql_append(sql, op, args) ⇒ Object

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


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# File 'lib/sequel/adapters/shared/postgres.rb', line 1539

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_returningObject

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).


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# File 'lib/sequel/adapters/shared/postgres.rb', line 1576

def disable_insert_returning
  clone(:disable_insert_returning=>true)
end

#explain(opts = OPTS) ⇒ Object

Return the results of an EXPLAIN query as a string


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# File 'lib/sequel/adapters/shared/postgres.rb', line 1581

def explain(opts=OPTS)
  with_sql((opts[:analyze] ? 'EXPLAIN ANALYZE ' : 'EXPLAIN ') + select_sql).map(:'QUERY PLAN').join("\r\n")
end

#for_shareObject

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


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# File 'lib/sequel/adapters/shared/postgres.rb', line 1586

def for_share
  lock_style(:share)
end

#full_text_search(cols, terms, opts = OPTS) ⇒ Object

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 or :phrase 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.


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# File 'lib/sequel/adapters/shared/postgres.rb', line 1609

def full_text_search(cols, terms, opts = OPTS)
  lang = Sequel.cast(opts[:language] || 'simple', :regconfig)

  unless opts[:tsvector]
    phrase_cols = full_text_string_join(cols)
    cols = Sequel.function(:to_tsvector, lang, phrase_cols)
  end

  unless opts[:tsquery]
    phrase_terms = terms.is_a?(Array) ? terms.join(' | ') : terms

    query_func = case to_tsquery = opts[:to_tsquery]
    when :phrase, :plain
      :"#{to_tsquery}to_tsquery"
    else
      (opts[:phrase] || opts[:plain]) ? :plainto_tsquery : :to_tsquery
    end

    terms = Sequel.function(query_func, lang, phrase_terms)
  end

  ds = where(Sequel.lit(["", " @@ ", ""], cols, terms))

  if opts[:phrase]
    raise Error, "can't use :phrase with either :tsvector or :tsquery arguments to full_text_search together" if opts[:tsvector] || opts[:tsquery]
    ds = ds.grep(phrase_cols, "%#{escape_like(phrase_terms)}%", :case_insensitive=>true)
  end

  if opts[:rank]
    ds = ds.reverse{ts_rank_cd(cols, terms)}
  end

  if opts[:headline]
    ds = ds.select_append{ts_headline(lang, phrase_cols, terms).as(:headline)}
  end

  ds
end

#insert(*values) ⇒ Object

Insert given values into the database.


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# File 'lib/sequel/adapters/shared/postgres.rb', line 1649

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) ⇒ Object

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)

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# File 'lib/sequel/adapters/shared/postgres.rb', line 1700

def insert_conflict(opts=OPTS)
  clone(:insert_conflict => opts)
end

#insert_ignoreObject

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

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# File 'lib/sequel/adapters/shared/postgres.rb', line 1710

def insert_ignore
  insert_conflict
end

#insert_select(*values) ⇒ Object

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.


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# File 'lib/sequel/adapters/shared/postgres.rb', line 1717

def insert_select(*values)
  return unless supports_insert_select?
  # Handle case where query does not return a row
  server?(:default).with_sql_first(insert_select_sql(*values)) || false
end

#insert_select_sql(*values) ⇒ Object

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


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# File 'lib/sequel/adapters/shared/postgres.rb', line 1725

def insert_select_sql(*values)
  ds = opts[:returning] ? self : returning
  ds.insert_sql(*values)
end

#lock(mode, opts = OPTS) ⇒ Object

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.


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# File 'lib/sequel/adapters/shared/postgres.rb', line 1735

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

#overriding_system_valueObject

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.


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# File 'lib/sequel/adapters/shared/postgres.rb', line 1754

def overriding_system_value
  clone(:override=>:system)
end

#overriding_user_valueObject

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


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# File 'lib/sequel/adapters/shared/postgres.rb', line 1760

def overriding_user_value
  clone(:override=>:user)
end

#supports_cte?(type = :select) ⇒ Boolean

Returns:

  • (Boolean)

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# File 'lib/sequel/adapters/shared/postgres.rb', line 1764

def supports_cte?(type=:select)
  if type == :select
    server_version >= 80400
  else
    server_version >= 90100
  end
end

#supports_cte_in_subqueries?Boolean

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

Returns:

  • (Boolean)

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# File 'lib/sequel/adapters/shared/postgres.rb', line 1774

def supports_cte_in_subqueries?
  supports_cte?
end

#supports_distinct_on?Boolean

DISTINCT ON is a PostgreSQL extension

Returns:

  • (Boolean)

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# File 'lib/sequel/adapters/shared/postgres.rb', line 1779

def supports_distinct_on?
  true
end

#supports_group_cube?Boolean

PostgreSQL 9.5+ supports GROUP CUBE

Returns:

  • (Boolean)

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# File 'lib/sequel/adapters/shared/postgres.rb', line 1784

def supports_group_cube?
  server_version >= 90500
end

#supports_group_rollup?Boolean

PostgreSQL 9.5+ supports GROUP ROLLUP

Returns:

  • (Boolean)

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# File 'lib/sequel/adapters/shared/postgres.rb', line 1789

def supports_group_rollup?
  server_version >= 90500
end

#supports_grouping_sets?Boolean

PostgreSQL 9.5+ supports GROUPING SETS

Returns:

  • (Boolean)

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# File 'lib/sequel/adapters/shared/postgres.rb', line 1794

def supports_grouping_sets?
  server_version >= 90500
end

#supports_insert_conflict?Boolean

PostgreSQL 9.5+ supports the ON CONFLICT clause to INSERT.

Returns:

  • (Boolean)

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# File 'lib/sequel/adapters/shared/postgres.rb', line 1804

def supports_insert_conflict?
  server_version >= 90500
end

#supports_insert_select?Boolean

True unless insert returning has been disabled for this dataset.

Returns:

  • (Boolean)

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# File 'lib/sequel/adapters/shared/postgres.rb', line 1799

def supports_insert_select?
  !@opts[:disable_insert_returning]
end

#supports_lateral_subqueries?Boolean

PostgreSQL 9.3+ supports lateral subqueries

Returns:

  • (Boolean)

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# File 'lib/sequel/adapters/shared/postgres.rb', line 1809

def supports_lateral_subqueries?
  server_version >= 90300
end

#supports_modifying_joins?Boolean

PostgreSQL supports modifying joined datasets

Returns:

  • (Boolean)

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# File 'lib/sequel/adapters/shared/postgres.rb', line 1814

def supports_modifying_joins?
  true
end

#supports_nowait?Boolean

PostgreSQL supports NOWAIT.

Returns:

  • (Boolean)

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# File 'lib/sequel/adapters/shared/postgres.rb', line 1819

def supports_nowait?
  true
end

#supports_regexp?Boolean

PostgreSQL supports pattern matching via regular expressions

Returns:

  • (Boolean)

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# File 'lib/sequel/adapters/shared/postgres.rb', line 1829

def supports_regexp?
  true
end

#supports_returning?(type) ⇒ Boolean

Returning is always supported.

Returns:

  • (Boolean)

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# File 'lib/sequel/adapters/shared/postgres.rb', line 1824

def supports_returning?(type)
  true
end

#supports_skip_locked?Boolean

PostgreSQL 9.5+ supports SKIP LOCKED.

Returns:

  • (Boolean)

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# File 'lib/sequel/adapters/shared/postgres.rb', line 1834

def supports_skip_locked?
  server_version >= 90500
end

#supports_timestamp_timezones?Boolean

PostgreSQL supports timezones in literal timestamps

Returns:

  • (Boolean)

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# File 'lib/sequel/adapters/shared/postgres.rb', line 1839

def supports_timestamp_timezones?
  true
end

#supports_window_clause?Boolean

PostgreSQL 8.4+ supports WINDOW clause.

Returns:

  • (Boolean)

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# File 'lib/sequel/adapters/shared/postgres.rb', line 1844

def supports_window_clause?
  server_version >= 80400
end

#supports_window_function_frame_option?(option) ⇒ Boolean

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

Returns:

  • (Boolean)

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# File 'lib/sequel/adapters/shared/postgres.rb', line 1855

def supports_window_function_frame_option?(option)
  case option
  when :rows, :range
    true
  when :offset
    server_version >= 90000
  when :groups, :exclude
    server_version >= 110000
  end
end

#supports_window_functions?Boolean

PostgreSQL 8.4+ supports window functions

Returns:

  • (Boolean)

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# File 'lib/sequel/adapters/shared/postgres.rb', line 1849

def supports_window_functions?
  server_version >= 80400
end

#truncate(opts = OPTS) ⇒ Object

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

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# File 'lib/sequel/adapters/shared/postgres.rb', line 1882

def truncate(opts = OPTS)
  if opts.empty?
    super()
  else
    clone(:truncate_opts=>opts).truncate
  end
end

#with_tiesObject

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.


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# File 'lib/sequel/adapters/shared/postgres.rb', line 1893

def with_ties
  clone(:limit_with_ties=>true)
end