Module Sequel::Postgres::DatabaseMethods
In: lib/sequel/adapters/shared/postgres.rb

Methods shared by Database instances that connect to PostgreSQL.

Methods

Constants

PREPARED_ARG_PLACEHOLDER = LiteralString.new('$').freeze
RE_CURRVAL_ERROR = /currval of sequence "(.*)" is not yet defined in this session|relation "(.*)" does not exist/.freeze
FOREIGN_KEY_LIST_ON_DELETE_MAP = {'a'.freeze=>:no_action, 'r'.freeze=>:restrict, 'c'.freeze=>:cascade, 'n'.freeze=>:set_null, 'd'.freeze=>:set_default}.freeze
POSTGRES_DEFAULT_RE = /\A(?:B?('.*')::[^']+|\((-?\d+(?:\.\d+)?)\))\z/
UNLOGGED = 'UNLOGGED '.freeze
SELECT_CUSTOM_SEQUENCE_SQL = (<<-end_sql SELECT name.nspname AS "schema", CASE WHEN split_part(def.adsrc, '''', 2) ~ '.' THEN substr(split_part(def.adsrc, '''', 2), strpos(split_part(def.adsrc, '''', 2), '.')+1) ELSE split_part(def.adsrc, '''', 2) END AS "sequence" FROM pg_class t JOIN pg_namespace name ON (t.relnamespace = name.oid) JOIN pg_attribute attr ON (t.oid = attrelid) JOIN pg_attrdef def ON (adrelid = attrelid AND adnum = attnum) JOIN pg_constraint cons ON (conrelid = adrelid AND adnum = conkey[1]) WHERE cons.contype = 'p' AND def.adsrc ~* 'nextval' end_sql   SQL fragment for custom sequences (ones not created by serial primary key), Returning the schema and literal form of the sequence name, by parsing the column defaults table.
SELECT_PK_SQL = (<<-end_sql SELECT pg_attribute.attname AS pk FROM pg_class, pg_attribute, pg_index, pg_namespace WHERE pg_class.oid = pg_attribute.attrelid AND pg_class.relnamespace = pg_namespace.oid AND pg_class.oid = pg_index.indrelid AND pg_index.indkey[0] = pg_attribute.attnum AND pg_index.indisprimary = 't' end_sql   SQL fragment for determining primary key column for the given table. Only returns the first primary key if the table has a composite primary key.
SELECT_SERIAL_SEQUENCE_SQL = (<<-end_sql SELECT name.nspname AS "schema", seq.relname AS "sequence" FROM pg_class seq, pg_attribute attr, pg_depend dep, pg_namespace name, pg_constraint cons, pg_class t WHERE seq.oid = dep.objid AND seq.relnamespace = name.oid AND seq.relkind = 'S' AND attr.attrelid = dep.refobjid AND attr.attnum = dep.refobjsubid AND attr.attrelid = cons.conrelid AND attr.attnum = cons.conkey[1] AND attr.attrelid = t.oid AND cons.contype = 'p' end_sql   SQL fragment for getting sequence associated with table‘s primary key, assuming it was a serial primary key column.
VALID_CLIENT_MIN_MESSAGES = %w'DEBUG5 DEBUG4 DEBUG3 DEBUG2 DEBUG1 LOG NOTICE WARNING ERROR FATAL PANIC'.freeze
EXCLUSION_CONSTRAINT_SQL_STATE = '23P01'.freeze
DATABASE_ERROR_REGEXPS = [ # Add this check first, since otherwise it's possible for users to control # which exception class is generated. [/invalid input syntax/, DatabaseError], [/duplicate key value violates unique constraint/, UniqueConstraintViolation], [/violates foreign key constraint/, ForeignKeyConstraintViolation], [/violates check constraint/, CheckConstraintViolation], [/violates not-null constraint/, NotNullConstraintViolation], [/conflicting key value violates exclusion constraint/, ExclusionConstraintViolation], [/could not serialize access/, SerializationFailure], ].freeze

Attributes

conversion_procs  [R]  A hash of conversion procs, keyed by type integer (oid) and having callable values for the conversion proc for that type.

Public Instance methods

Commit an existing prepared transaction with the given transaction identifier string.

[Source]

     # File lib/sequel/adapters/shared/postgres.rb, line 159
159:       def commit_prepared_transaction(transaction_id)
160:         run("COMMIT PREPARED #{literal(transaction_id)}")
161:       end

Creates the function in the database. Arguments:

  • name : name of the function to create
  • definition : string definition of the function, or object file for a dynamically loaded C function.
  • opts : options hash:
    • :args : function arguments, can be either a symbol or string specifying a type or an array of 1-3 elements:
      • element 1 : argument data type
      • element 2 : argument name
      • element 3 : argument mode (e.g. in, out, inout)
    • :behavior : Should be IMMUTABLE, STABLE, or VOLATILE. PostgreSQL assumes VOLATILE by default.
    • :cost : The estimated cost of the function, used by the query planner.
    • :language : The language the function uses. SQL is the default.
    • :link_symbol : For a dynamically loaded see function, the function‘s link symbol if different from the definition argument.
    • :returns : The data type returned by the function. If you are using OUT or INOUT argument modes, this is ignored. Otherwise, if this is not specified, void is used by default to specify the function is not supposed to return a value.
    • :rows : The estimated number of rows the function will return. Only use if the function returns SETOF something.
    • :security_definer : Makes the privileges of the function the same as the privileges of the user who defined the function instead of the privileges of the user who runs the function. There are security implications when doing this, see the PostgreSQL documentation.
    • :set : Configuration variables to set while the function is being run, can be a hash or an array of two pairs. search_path is often used here if :security_definer is used.
    • :strict : Makes the function return NULL when any argument is NULL.

[Source]

     # File lib/sequel/adapters/shared/postgres.rb, line 183
183:       def create_function(name, definition, opts=OPTS)
184:         self << create_function_sql(name, definition, opts)
185:       end

Create the procedural language in the database. Arguments:

  • name : Name of the procedural language (e.g. plpgsql)
  • opts : options hash:
    • :handler : The name of a previously registered function used as a call handler for this language.
    • :replace : Replace the installed language if it already exists (on PostgreSQL 9.0+).
    • :trusted : Marks the language being created as trusted, allowing unprivileged users to create functions using this language.
    • :validator : The name of previously registered function used as a validator of functions defined in this language.

[Source]

     # File lib/sequel/adapters/shared/postgres.rb, line 194
194:       def create_language(name, opts=OPTS)
195:         self << create_language_sql(name, opts)
196:       end

Create a schema in the database. Arguments:

  • name : Name of the schema (e.g. admin)
  • opts : options hash:
    • :if_not_exists : Don‘t raise an error if the schema already exists (PostgreSQL 9.3+)
    • :owner : The owner to set for the schema (defaults to current user if not specified)

[Source]

     # File lib/sequel/adapters/shared/postgres.rb, line 203
203:       def create_schema(name, opts=OPTS)
204:         self << create_schema_sql(name, opts)
205:       end

Create a trigger in the database. Arguments:

  • table : the table on which this trigger operates
  • name : the name of this trigger
  • function : the function to call for this trigger, which should return type trigger.
  • opts : options hash:
    • :after : Calls the trigger after execution instead of before.
    • :args : An argument or array of arguments to pass to the function.
    • :each_row : Calls the trigger for each row instead of for each statement.
    • :events : Can be :insert, :update, :delete, or an array of any of those. Calls the trigger whenever that type of statement is used. By default, the trigger is called for insert, update, or delete.

[Source]

     # File lib/sequel/adapters/shared/postgres.rb, line 217
217:       def create_trigger(table, name, function, opts=OPTS)
218:         self << create_trigger_sql(table, name, function, opts)
219:       end

PostgreSQL uses the :postgres database type.

[Source]

     # File lib/sequel/adapters/shared/postgres.rb, line 222
222:       def database_type
223:         :postgres
224:       end

Use PostgreSQL‘s DO syntax to execute an anonymous code block. The code should be the literal code string to use in the underlying procedural language. Options:

:language :The procedural language the code is written in. The PostgreSQL default is plpgsql. Can be specified as a string or a symbol.

[Source]

     # File lib/sequel/adapters/shared/postgres.rb, line 231
231:       def do(code, opts=OPTS)
232:         language = opts[:language]
233:         run "DO #{"LANGUAGE #{literal(language.to_s)} " if language}#{literal(code)}"
234:       end

Drops the function from the database. Arguments:

  • name : name of the function to drop
  • opts : options hash:
    • :args : The arguments for the function. See create_function_sql.
    • :cascade : Drop other objects depending on this function.
    • :if_exists : Don‘t raise an error if the function doesn‘t exist.

[Source]

     # File lib/sequel/adapters/shared/postgres.rb, line 242
242:       def drop_function(name, opts=OPTS)
243:         self << drop_function_sql(name, opts)
244:       end

Drops a procedural language from the database. Arguments:

  • name : name of the procedural language to drop
  • opts : options hash:
    • :cascade : Drop other objects depending on this function.
    • :if_exists : Don‘t raise an error if the function doesn‘t exist.

[Source]

     # File lib/sequel/adapters/shared/postgres.rb, line 251
251:       def drop_language(name, opts=OPTS)
252:         self << drop_language_sql(name, opts)
253:       end

Drops a schema from the database. Arguments:

  • name : name of the schema to drop
  • opts : options hash:
    • :cascade : Drop all objects in this schema.
    • :if_exists : Don‘t raise an error if the schema doesn‘t exist.

[Source]

     # File lib/sequel/adapters/shared/postgres.rb, line 260
260:       def drop_schema(name, opts=OPTS)
261:         self << drop_schema_sql(name, opts)
262:       end

Drops a trigger from the database. Arguments:

  • table : table from which to drop the trigger
  • name : name of the trigger to drop
  • opts : options hash:
    • :cascade : Drop other objects depending on this function.
    • :if_exists : Don‘t raise an error if the function doesn‘t exist.

[Source]

     # File lib/sequel/adapters/shared/postgres.rb, line 270
270:       def drop_trigger(table, name, opts=OPTS)
271:         self << drop_trigger_sql(table, name, opts)
272:       end

Return full foreign key information using the pg system tables, including :name, :on_delete, :on_update, and :deferrable entries in the hashes.

[Source]

     # File lib/sequel/adapters/shared/postgres.rb, line 276
276:       def foreign_key_list(table, opts=OPTS)
277:         m = output_identifier_meth
278:         schema, _ = opts.fetch(:schema, schema_and_table(table))
279:         range = 0...32
280: 
281:         base_ds = metadata_dataset.
282:           from(:pg_constraint___co).
283:           join(:pg_class___cl, :oid=>:conrelid).
284:           where(:cl__relkind=>'r', :co__contype=>'f', :cl__oid=>regclass_oid(table))
285: 
286:         # We split the parsing into two separate queries, which are merged manually later.
287:         # This is because PostgreSQL stores both the referencing and referenced columns in
288:         # arrays, and I don't know a simple way to not create a cross product, as PostgreSQL
289:         # doesn't appear to have a function that takes an array and element and gives you
290:         # the index of that element in the array.
291: 
292:         ds = base_ds.
293:           join(:pg_attribute___att, :attrelid=>:oid, :attnum=>SQL::Function.new(:ANY, :co__conkey)).
294:           order(:co__conname, SQL::CaseExpression.new(range.map{|x| [SQL::Subscript.new(:co__conkey, [x]), x]}, 32, :att__attnum)).
295:           select(:co__conname___name, :att__attname___column, :co__confupdtype___on_update, :co__confdeltype___on_delete,
296:                  SQL::BooleanExpression.new(:AND, :co__condeferrable, :co__condeferred).as(:deferrable))
297: 
298:         ref_ds = base_ds.
299:           join(:pg_class___cl2, :oid=>:co__confrelid).
300:           join(:pg_attribute___att2, :attrelid=>:oid, :attnum=>SQL::Function.new(:ANY, :co__confkey)).
301:           order(:co__conname, SQL::CaseExpression.new(range.map{|x| [SQL::Subscript.new(:co__conkey, [x]), x]}, 32, :att2__attnum)).
302:           select(:co__conname___name, :cl2__relname___table, :att2__attname___refcolumn)
303: 
304:         # If a schema is given, we only search in that schema, and the returned :table
305:         # entry is schema qualified as well.
306:         if schema
307:           ref_ds = ref_ds.join(:pg_namespace___nsp2, :oid=>:cl2__relnamespace).
308:             select_more(:nsp2__nspname___schema)
309:         end
310: 
311:         h = {}
312:         fklod_map = FOREIGN_KEY_LIST_ON_DELETE_MAP 
313:         ds.each do |row|
314:           if r = h[row[:name]]
315:             r[:columns] << m.call(row[:column])
316:           else
317:             h[row[:name]] = {:name=>m.call(row[:name]), :columns=>[m.call(row[:column])], :on_update=>fklod_map[row[:on_update]], :on_delete=>fklod_map[row[:on_delete]], :deferrable=>row[:deferrable]}
318:           end
319:         end
320:         ref_ds.each do |row|
321:           r = h[row[:name]]
322:           r[:table] ||= schema ? SQL::QualifiedIdentifier.new(m.call(row[:schema]), m.call(row[:table])) : m.call(row[:table])
323:           r[:key] ||= []
324:           r[:key] << m.call(row[:refcolumn])
325:         end
326:         h.values
327:       end

Use the pg_* system tables to determine indexes on a table

[Source]

     # File lib/sequel/adapters/shared/postgres.rb, line 330
330:       def indexes(table, opts=OPTS)
331:         m = output_identifier_meth
332:         range = 0...32
333:         attnums = server_version >= 80100 ? SQL::Function.new(:ANY, :ind__indkey) : range.map{|x| SQL::Subscript.new(:ind__indkey, [x])}
334:         ds = metadata_dataset.
335:           from(:pg_class___tab).
336:           join(:pg_index___ind, :indrelid=>:oid).
337:           join(:pg_class___indc, :oid=>:indexrelid).
338:           join(:pg_attribute___att, :attrelid=>:tab__oid, :attnum=>attnums).
339:           left_join(:pg_constraint___con, :conname=>:indc__relname).
340:           filter(:indc__relkind=>'i', :ind__indisprimary=>false, :indexprs=>nil, :indpred=>nil, :indisvalid=>true, :tab__oid=>regclass_oid(table, opts)).
341:           order(:indc__relname, SQL::CaseExpression.new(range.map{|x| [SQL::Subscript.new(:ind__indkey, [x]), x]}, 32, :att__attnum)).
342:           select(:indc__relname___name, :ind__indisunique___unique, :att__attname___column, :con__condeferrable___deferrable)
343: 
344:         ds.filter!(:indisready=>true, :indcheckxmin=>false) if server_version >= 80300
345: 
346:         indexes = {}
347:         ds.each do |r|
348:           i = indexes[m.call(r[:name])] ||= {:columns=>[], :unique=>r[:unique], :deferrable=>r[:deferrable]}
349:           i[:columns] << m.call(r[:column])
350:         end
351:         indexes
352:       end

Dataset containing all current database locks

[Source]

     # File lib/sequel/adapters/shared/postgres.rb, line 355
355:       def locks
356:         dataset.from(:pg_class).join(:pg_locks, :relation=>:relfilenode).select(:pg_class__relname, Sequel::SQL::ColumnAll.new(:pg_locks))
357:       end

Notifies the given channel. See the PostgreSQL NOTIFY documentation. Options:

:payload :The payload string to use for the NOTIFY statement. Only supported in PostgreSQL 9.0+.
:server :The server to which to send the NOTIFY statement, if the sharding support is being used.

[Source]

     # File lib/sequel/adapters/shared/postgres.rb, line 365
365:       def notify(channel, opts=OPTS)
366:         sql = "NOTIFY "
367:         dataset.send(:identifier_append, sql, channel)
368:         if payload = opts[:payload]
369:           sql << ", "
370:           dataset.literal_append(sql, payload.to_s)
371:         end
372:         execute_ddl(sql, opts)
373:       end

Return primary key for the given table.

[Source]

     # File lib/sequel/adapters/shared/postgres.rb, line 376
376:       def primary_key(table, opts=OPTS)
377:         quoted_table = quote_schema_table(table)
378:         Sequel.synchronize{return @primary_keys[quoted_table] if @primary_keys.has_key?(quoted_table)}
379:         sql = "#{SELECT_PK_SQL} AND pg_class.oid = #{literal(regclass_oid(table, opts))}"
380:         value = fetch(sql).single_value
381:         Sequel.synchronize{@primary_keys[quoted_table] = value}
382:       end

Return the sequence providing the default for the primary key for the given table.

[Source]

     # File lib/sequel/adapters/shared/postgres.rb, line 385
385:       def primary_key_sequence(table, opts=OPTS)
386:         quoted_table = quote_schema_table(table)
387:         Sequel.synchronize{return @primary_key_sequences[quoted_table] if @primary_key_sequences.has_key?(quoted_table)}
388:         sql = "#{SELECT_SERIAL_SEQUENCE_SQL} AND t.oid = #{literal(regclass_oid(table, opts))}"
389:         if pks = fetch(sql).single_record
390:           value = literal(SQL::QualifiedIdentifier.new(pks[:schema], pks[:sequence]))
391:           Sequel.synchronize{@primary_key_sequences[quoted_table] = value}
392:         else
393:           sql = "#{SELECT_CUSTOM_SEQUENCE_SQL} AND t.oid = #{literal(regclass_oid(table, opts))}"
394:           if pks = fetch(sql).single_record
395:             value = literal(SQL::QualifiedIdentifier.new(pks[:schema], LiteralString.new(pks[:sequence])))
396:             Sequel.synchronize{@primary_key_sequences[quoted_table] = value}
397:           end
398:         end
399:       end

Refresh the materialized view with the given name.

  DB.refresh_view(:items_view)
  # REFRESH MATERIALIZED VIEW items_view

[Source]

     # File lib/sequel/adapters/shared/postgres.rb, line 405
405:       def refresh_view(name, opts=OPTS)
406:         run "REFRESH MATERIALIZED VIEW #{quote_schema_table(name)}"
407:       end

Reset the database‘s conversion procs, requires a server query if there any named types.

[Source]

     # File lib/sequel/adapters/shared/postgres.rb, line 411
411:       def reset_conversion_procs
412:         @conversion_procs = get_conversion_procs
413:       end

Reset the primary key sequence for the given table, basing it on the maximum current value of the table‘s primary key.

[Source]

     # File lib/sequel/adapters/shared/postgres.rb, line 417
417:       def reset_primary_key_sequence(table)
418:         return unless seq = primary_key_sequence(table)
419:         pk = SQL::Identifier.new(primary_key(table))
420:         db = self
421:         seq_ds = db.from(LiteralString.new(seq))
422:         s, t = schema_and_table(table)
423:         table = Sequel.qualify(s, t) if s
424:         get{setval(seq, db[table].select{coalesce(max(pk)+seq_ds.select{:increment_by}, seq_ds.select(:min_value))}, false)}
425:       end

Rollback an existing prepared transaction with the given transaction identifier string.

[Source]

     # File lib/sequel/adapters/shared/postgres.rb, line 429
429:       def rollback_prepared_transaction(transaction_id)
430:         run("ROLLBACK PREPARED #{literal(transaction_id)}")
431:       end

PostgreSQL uses SERIAL psuedo-type instead of AUTOINCREMENT for managing incrementing primary keys.

[Source]

     # File lib/sequel/adapters/shared/postgres.rb, line 435
435:       def serial_primary_key_options
436:         {:primary_key => true, :serial => true, :type=>Integer}
437:       end

The version of the PostgreSQL server, used for determining capability.

[Source]

     # File lib/sequel/adapters/shared/postgres.rb, line 440
440:       def server_version(server=nil)
441:         return @server_version if @server_version
442:         @server_version = synchronize(server) do |conn|
443:           (conn.server_version rescue nil) if conn.respond_to?(:server_version)
444:         end
445:         unless @server_version
446:           @server_version = if m = /PostgreSQL (\d+)\.(\d+)(?:(?:rc\d+)|\.(\d+))?/.match(fetch('SELECT version()').single_value)
447:             (m[1].to_i * 10000) + (m[2].to_i * 100) + m[3].to_i
448:           else
449:             0
450:           end
451:         end
452:         warn 'Sequel no longer supports PostgreSQL <8.2, some things may not work' if @server_version < 80200
453:         @server_version
454:       end

PostgreSQL supports CREATE TABLE IF NOT EXISTS on 9.1+

[Source]

     # File lib/sequel/adapters/shared/postgres.rb, line 457
457:       def supports_create_table_if_not_exists?
458:         server_version >= 90100
459:       end

PostgreSQL 9.0+ supports some types of deferrable constraints beyond foreign key constraints.

[Source]

     # File lib/sequel/adapters/shared/postgres.rb, line 462
462:       def supports_deferrable_constraints?
463:         server_version >= 90000
464:       end

PostgreSQL supports deferrable foreign key constraints.

[Source]

     # File lib/sequel/adapters/shared/postgres.rb, line 467
467:       def supports_deferrable_foreign_key_constraints?
468:         true
469:       end

PostgreSQL supports DROP TABLE IF EXISTS

[Source]

     # File lib/sequel/adapters/shared/postgres.rb, line 472
472:       def supports_drop_table_if_exists?
473:         true
474:       end

PostgreSQL supports prepared transactions (two-phase commit) if max_prepared_transactions is greater than 0.

[Source]

     # File lib/sequel/adapters/shared/postgres.rb, line 478
478:       def supports_prepared_transactions?
479:         return @supports_prepared_transactions if defined?(@supports_prepared_transactions)
480:         @supports_prepared_transactions = self['SHOW max_prepared_transactions'].get.to_i > 0
481:       end

PostgreSQL supports savepoints

[Source]

     # File lib/sequel/adapters/shared/postgres.rb, line 484
484:       def supports_savepoints?
485:         true
486:       end

PostgreSQL supports transaction isolation levels

[Source]

     # File lib/sequel/adapters/shared/postgres.rb, line 489
489:       def supports_transaction_isolation_levels?
490:         true
491:       end

PostgreSQL supports transaction DDL statements.

[Source]

     # File lib/sequel/adapters/shared/postgres.rb, line 494
494:       def supports_transactional_ddl?
495:         true
496:       end

Array of symbols specifying table names in the current database. The dataset used is yielded to the block if one is provided, otherwise, an array of symbols of table names is returned.

Options:

:qualify :Return the tables as Sequel::SQL::QualifiedIdentifier instances, using the schema the table is located in as the qualifier.
:schema :The schema to search
:server :The server to use

[Source]

     # File lib/sequel/adapters/shared/postgres.rb, line 507
507:       def tables(opts=OPTS, &block)
508:         pg_class_relname('r', opts, &block)
509:       end

Check whether the given type name string/symbol (e.g. :hstore) is supported by the database.

[Source]

     # File lib/sequel/adapters/shared/postgres.rb, line 513
513:       def type_supported?(type)
514:         @supported_types ||= {}
515:         @supported_types.fetch(type){@supported_types[type] = (from(:pg_type).filter(:typtype=>'b', :typname=>type.to_s).count > 0)}
516:       end

Array of symbols specifying view names in the current database.

Options:

:qualify :Return the views as Sequel::SQL::QualifiedIdentifier instances, using the schema the view is located in as the qualifier.
:schema :The schema to search
:server :The server to use

[Source]

     # File lib/sequel/adapters/shared/postgres.rb, line 525
525:       def views(opts=OPTS)
526:         pg_class_relname('v', opts)
527:       end

[Validate]