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

Methods shared by Database instances that connect to PostgreSQL.

### Methods

commit_prepared_transaction create_function create_language create_schema create_trigger database_type drop_function drop_language drop_schema drop_trigger extension foreign_key_list indexes locks notify primary_key primary_key_sequence reset_conversion_procs reset_primary_key_sequence rollback_prepared_transaction serial_primary_key_options server_version supports_create_table_if_not_exists? supports_drop_table_if_exists? supports_prepared_transactions? supports_savepoints? supports_transaction_isolation_levels? supports_transactional_ddl? tables type_supported? views

### Constants

EXCLUDE_SCHEMAS | = | /pg_*|information_schema/i
PREPARED_ARG_PLACEHOLDER | = | LiteralString.new('$').freeze
RE_CURRVAL_ERROR | = | /currval of sequence "(.*)" is not yet defined in this session|relation "(.*)" does not exist/.freeze
SYSTEM_TABLE_REGEXP | = | /^pg|sql/.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
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 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 cons.contype = 'p' end_sql |  | SQL fragment for getting sequence associated with table‘s primary key, assuming it was a serial primary key column.
RESET_PROCS_EXTENSIONS | = | [:pg_array, :pg_hstore, :pg_inet, :pg_interval, :pg_json, :pg_range].freeze |  | The Sequel extensions that require reseting of the conversion procs.

### 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_prepared_transaction(transaction_id)

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

[Source]

         # File lib/sequel/adapters/shared/postgres.rb, line 163
    163:       def commit_prepared_transaction(transaction_id)
    164:         run("COMMIT PREPARED #{literal(transaction_id)}")
    165:       end

create_function(name, definition, opts={})

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 187
    187:       def create_function(name, definition, opts={})
    188:         self << create_function_sql(name, definition, opts)
    189:       end

create_language(name, opts={})

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 198
    198:       def create_language(name, opts={})
    199:         self << create_language_sql(name, opts)
    200:       end

create_schema(name)

Create a schema in the database. Arguments:

- name : Name of the schema (e.g. admin)

[Source]

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

create_trigger(table, name, function, opts={})

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 218
    218:       def create_trigger(table, name, function, opts={})
    219:         self << create_trigger_sql(table, name, function, opts)
    220:       end

database_type()

PostgreSQL uses the :postgres database type.

[Source]

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

drop_function(name, opts={})

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 233
    233:       def drop_function(name, opts={})
    234:         self << drop_function_sql(name, opts)
    235:       end

drop_language(name, opts={})

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 242
    242:       def drop_language(name, opts={})
    243:         self << drop_language_sql(name, opts)
    244:       end

drop_schema(name, opts={})

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 251
    251:       def drop_schema(name, opts={})
    252:         self << drop_schema_sql(name, opts)
    253:       end

drop_trigger(table, name, opts={})

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 261
    261:       def drop_trigger(table, name, opts={})
    262:         self << drop_trigger_sql(table, name, opts)
    263:       end

extension(*exts)

If any of the extensions that require reseting the conversion procs is loaded, reset them. This is done here so that if you load multiple pg_* extensions in the same call, the conversion procs are only reset once instead of once for every extension.

[Source]

         # File lib/sequel/adapters/shared/postgres.rb, line 269
    269:       def extension(*exts)
    270:         super
    271:         unless (RESET_PROCS_EXTENSIONS & exts).empty?
    272:           reset_conversion_procs
    273:         end
    274:       end

foreign_key_list(table, opts={})

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

indexes(table, opts={})

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

[Source]

         # File lib/sequel/adapters/shared/postgres.rb, line 335
    335:       def indexes(table, opts={})
    336:         m = output_identifier_meth
    337:         im = input_identifier_meth
    338:         schema, table = schema_and_table(table)
    339:         range = 0...32
    340:         attnums = server_version >= 80100 ? SQL::Function.new(:ANY, :ind__indkey) : range.map{|x| SQL::Subscript.new(:ind__indkey, [x])}
    341:         ds = metadata_dataset.
    342:           from(:pg_class___tab).
    343:           join(:pg_index___ind, :indrelid=>:oid, im.call(table)=>:relname).
    344:           join(:pg_class___indc, :oid=>:indexrelid).
    345:           join(:pg_attribute___att, :attrelid=>:tab__oid, :attnum=>attnums).
    346:           filter(:indc__relkind=>'i', :ind__indisprimary=>false, :indexprs=>nil, :indpred=>nil, :indisvalid=>true).
    347:           order(:indc__relname, SQL::CaseExpression.new(range.map{|x| [SQL::Subscript.new(:ind__indkey, [x]), x]}, 32, :att__attnum)).
    348:           select(:indc__relname___name, :ind__indisunique___unique, :att__attname___column)
    349:
    350:         ds.join!(:pg_namespace___nsp, :oid=>:tab__relnamespace, :nspname=>schema.to_s) if schema
    351:         ds.filter!(:indisready=>true, :indcheckxmin=>false) if server_version >= 80300
    352:
    353:         indexes = {}
    354:         ds.each do |r|
    355:           i = indexes[m.call(r[:name])] ||= {:columns=>[], :unique=>r[:unique]}
    356:           i[:columns] << m.call(r[:column])
    357:         end
    358:         indexes
    359:       end

locks()

Dataset containing all current database locks

[Source]

         # File lib/sequel/adapters/shared/postgres.rb, line 362
    362:       def locks
    363:         dataset.from(:pg_class).join(:pg_locks, :relation=>:relfilenode).select(:pg_class__relname, Sequel::SQL::ColumnAll.new(:pg_locks))
    364:       end

notify(channel, opts={})

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 372
    372:       def notify(channel, opts={})
    373:         execute_ddl("NOTIFY #{channel}#{", #{literal(opts[:payload].to_s)}" if opts[:payload]}", opts)
    374:       end

primary_key(table, opts={})

Return primary key for the given table.

[Source]

         # File lib/sequel/adapters/shared/postgres.rb, line 377
    377:       def primary_key(table, opts={})
    378:         quoted_table = quote_schema_table(table)
    379:         @primary_keys.fetch(quoted_table) do
    380:           schema, table = schema_and_table(table)
    381:           sql = "#{SELECT_PK_SQL} AND pg_class.relname = #{literal(table)}"
    382:           sql << "AND pg_namespace.nspname = #{literal(schema)}" if schema
    383:           @primary_keys[quoted_table] = fetch(sql).single_value
    384:         end
    385:       end

primary_key_sequence(table, opts={})

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

[Source]

         # File lib/sequel/adapters/shared/postgres.rb, line 388
    388:       def primary_key_sequence(table, opts={})
    389:         quoted_table = quote_schema_table(table)
    390:         @primary_key_sequences.fetch(quoted_table) do
    391:           schema, table = schema_and_table(table)
    392:           table = literal(table)
    393:           sql = "#{SELECT_SERIAL_SEQUENCE_SQL} AND seq.relname = #{table}"
    394:           sql << " AND name.nspname = #{literal(schema)}" if schema
    395:           unless pks = fetch(sql).single_record
    396:             sql = "#{SELECT_CUSTOM_SEQUENCE_SQL} AND t.relname = #{table}"
    397:             sql << " AND name.nspname = #{literal(schema)}" if schema
    398:             pks = fetch(sql).single_record
    399:           end
    400:
    401:           @primary_key_sequences[quoted_table] = if pks
    402:             literal(SQL::QualifiedIdentifier.new(pks[:schema], LiteralString.new(pks[:sequence])))
    403:           end
    404:         end
    405:       end

reset_conversion_procs()

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

[Source]

         # File lib/sequel/adapters/shared/postgres.rb, line 409
    409:       def reset_conversion_procs
    410:         @conversion_procs = get_conversion_procs
    411:       end

reset_primary_key_sequence(table)

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

[Source]

         # File lib/sequel/adapters/shared/postgres.rb, line 415
    415:       def reset_primary_key_sequence(table)
    416:         return unless seq = primary_key_sequence(table)
    417:         pk = SQL::Identifier.new(primary_key(table))
    418:         db = self
    419:         seq_ds = db.from(LiteralString.new(seq))
    420:         get{setval(seq, db[table].select{coalesce(max(pk)+seq_ds.select{:increment_by}, seq_ds.select(:min_value))}, false)}
    421:       end

rollback_prepared_transaction(transaction_id)

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

[Source]

         # File lib/sequel/adapters/shared/postgres.rb, line 425
    425:       def rollback_prepared_transaction(transaction_id)
    426:         run("ROLLBACK PREPARED #{literal(transaction_id)}")
    427:       end

serial_primary_key_options()

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

[Source]

         # File lib/sequel/adapters/shared/postgres.rb, line 431
    431:       def serial_primary_key_options
    432:         {:primary_key => true, :serial => true, :type=>Integer}
    433:       end

server_version(server=nil)

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

[Source]

         # File lib/sequel/adapters/shared/postgres.rb, line 436
    436:       def server_version(server=nil)
    437:         return @server_version if @server_version
    438:         @server_version = synchronize(server) do |conn|
    439:           (conn.server_version rescue nil) if conn.respond_to?(:server_version)
    440:         end
    441:         unless @server_version
    442:           @server_version = if m = /PostgreSQL (\d+)\.(\d+)(?:(?:rc\d+)|\.(\d+))?/.match(fetch('SELECT version()').single_value)
    443:             (m[1].to_i * 10000) + (m[2].to_i * 100) + m[3].to_i
    444:           else
    445:             0
    446:           end
    447:         end
    448:         warn 'Sequel no longer supports PostgreSQL <8.2, some things may not work' if @server_version < 80200
    449:         @server_version
    450:       end

supports_create_table_if_not_exists?()

PostgreSQL supports CREATE TABLE IF NOT EXISTS on 9.1+

[Source]

         # File lib/sequel/adapters/shared/postgres.rb, line 453
    453:       def supports_create_table_if_not_exists?
    454:         server_version >= 90100
    455:       end

supports_drop_table_if_exists?()

PostgreSQL supports DROP TABLE IF EXISTS

[Source]

         # File lib/sequel/adapters/shared/postgres.rb, line 458
    458:       def supports_drop_table_if_exists?
    459:         true
    460:       end

supports_prepared_transactions?()

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

[Source]

         # File lib/sequel/adapters/shared/postgres.rb, line 464
    464:       def supports_prepared_transactions?
    465:         return @supports_prepared_transactions if defined?(@supports_prepared_transactions)
    466:         @supports_prepared_transactions = self['SHOW max_prepared_transactions'].get.to_i > 0
    467:       end

supports_savepoints?()

PostgreSQL supports savepoints

[Source]

         # File lib/sequel/adapters/shared/postgres.rb, line 470
    470:       def supports_savepoints?
    471:         true
    472:       end

supports_transaction_isolation_levels?()

PostgreSQL supports transaction isolation levels

[Source]

         # File lib/sequel/adapters/shared/postgres.rb, line 475
    475:       def supports_transaction_isolation_levels?
    476:         true
    477:       end

supports_transactional_ddl?()

PostgreSQL supports transaction DDL statements.

[Source]

         # File lib/sequel/adapters/shared/postgres.rb, line 480
    480:       def supports_transactional_ddl?
    481:         true
    482:       end

tables(opts={}, &block)

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:

- :schema - The schema to search (default_schema by default)
- :server - The server to use

[Source]

         # File lib/sequel/adapters/shared/postgres.rb, line 491
    491:       def tables(opts={}, &block)
    492:         pg_class_relname('r', opts, &block)
    493:       end

type_supported?(type)

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 497
    497:       def type_supported?(type)
    498:         @supported_types ||= {}
    499:         @supported_types.fetch(type){@supported_types[type] = (from(:pg_type).filter(:typtype=>'b', :typname=>type.to_s).count > 0)}
    500:       end

views(opts={})

Array of symbols specifying view names in the current database.

Options:

- :schema - The schema to search (default_schema by default)
- :server - The server to use

[Source]

         # File lib/sequel/adapters/shared/postgres.rb, line 507
    507:       def views(opts={})
    508:         pg_class_relname('v', opts)
    509:       end

[Validate]