module Sequel::Postgres::DatabaseMethods

  1. lib/sequel/adapters/shared/postgres.rb
Parent: Postgres

Methods shared by Database instances that connect to PostgreSQL.

Constants

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  
EXCLUSION_CONSTRAINT_SQL_STATE = '23P01'.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/  
PREPARED_ARG_PLACEHOLDER = LiteralString.new('$').freeze  
RE_CURRVAL_ERROR = /currval of sequence "(.*)" is not yet defined in this session|relation "(.*)" does not exist/.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 ).strip.gsub(/\s+/, ' ').freeze  

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 ).strip.gsub(/\s+/, ' ').freeze  

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 ).strip.gsub(/\s+/, ' ').freeze  

SQL fragment for getting sequence associated with table’s primary key, assuming it was a serial primary key column.
UNLOGGED = 'UNLOGGED '.freeze  
VALID_CLIENT_MIN_MESSAGES = %w'DEBUG5 DEBUG4 DEBUG3 DEBUG2 DEBUG1 LOG NOTICE WARNING ERROR FATAL PANIC'.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_prepared_transaction (transaction_id)

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

[show source] 
# File lib/sequel/adapters/shared/postgres.rb, line 156
def commit_prepared_transaction(transaction_id)
  run("COMMIT PREPARED #{literal(transaction_id)}")
end
create_function (name, definition, opts=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.

[show source] 
# File lib/sequel/adapters/shared/postgres.rb, line 180
def create_function(name, definition, opts=OPTS)
  self << create_function_sql(name, definition, opts)
end
create_language (name, opts=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.

[show source] 
# File lib/sequel/adapters/shared/postgres.rb, line 191
def create_language(name, opts=OPTS)
  self << create_language_sql(name, opts)
end
create_schema (name, opts=OPTS)

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)

[show source] 
# File lib/sequel/adapters/shared/postgres.rb, line 200
def create_schema(name, opts=OPTS)
  self << create_schema_sql(name, opts)
end
create_trigger (table, name, function, opts=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.

[show source] 
# File lib/sequel/adapters/shared/postgres.rb, line 214
def create_trigger(table, name, function, opts=OPTS)
  self << create_trigger_sql(table, name, function, opts)
end
database_type ()

PostgreSQL uses the :postgres database type.

[show source] 
# File lib/sequel/adapters/shared/postgres.rb, line 219
def database_type
  :postgres
end
do (code, opts=OPTS)

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.

[show source] 
# File lib/sequel/adapters/shared/postgres.rb, line 228
def do(code, opts=OPTS)
  language = opts[:language]
  run "DO #{"LANGUAGE #{literal(language.to_s)} " if language}#{literal(code)}"
end
drop_function (name, opts=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.

[show source] 
# File lib/sequel/adapters/shared/postgres.rb, line 239
def drop_function(name, opts=OPTS)
  self << drop_function_sql(name, opts)
end
drop_language (name, opts=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.

[show source] 
# File lib/sequel/adapters/shared/postgres.rb, line 248
def drop_language(name, opts=OPTS)
  self << drop_language_sql(name, opts)
end
drop_schema (name, opts=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.

[show source] 
# File lib/sequel/adapters/shared/postgres.rb, line 257
def drop_schema(name, opts=OPTS)
  self << drop_schema_sql(name, opts)
end
drop_trigger (table, name, opts=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.

[show source] 
# File lib/sequel/adapters/shared/postgres.rb, line 267
def drop_trigger(table, name, opts=OPTS)
  self << drop_trigger_sql(table, name, opts)
end
foreign_key_list (table, opts=OPTS)

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

[show source] 
# File lib/sequel/adapters/shared/postgres.rb, line 273
def foreign_key_list(table, opts=OPTS)
  m = output_identifier_meth
  schema, _ = opts.fetch(:schema, schema_and_table(table))
  range = 0...32

  base_ds = metadata_dataset.
    from(:pg_constraint___co).
    join(:pg_class___cl, :oid=>:conrelid).
    where(:cl__relkind=>'r', :co__contype=>'f', :cl__oid=>regclass_oid(table))

  # We split the parsing into two separate queries, which are merged manually later.
  # This is because PostgreSQL stores both the referencing and referenced columns in
  # arrays, and I don't know a simple way to not create a cross product, as PostgreSQL
  # doesn't appear to have a function that takes an array and element and gives you
  # the index of that element in the array.

  ds = base_ds.
    join(:pg_attribute___att, :attrelid=>:oid, :attnum=>SQL::Function.new(:ANY, :co__conkey)).
    order(:co__conname, SQL::CaseExpression.new(range.map{|x| [SQL::Subscript.new(:co__conkey, [x]), x]}, 32, :att__attnum)).
    select(:co__conname___name, :att__attname___column, :co__confupdtype___on_update, :co__confdeltype___on_delete,
           SQL::BooleanExpression.new(:AND, :co__condeferrable, :co__condeferred).as(:deferrable))

  ref_ds = base_ds.
    join(:pg_class___cl2, :oid=>:co__confrelid).
    join(:pg_attribute___att2, :attrelid=>:oid, :attnum=>SQL::Function.new(:ANY, :co__confkey)).
    order(:co__conname, SQL::CaseExpression.new(range.map{|x| [SQL::Subscript.new(:co__conkey, [x]), x]}, 32, :att2__attnum)).
    select(:co__conname___name, :cl2__relname___table, :att2__attname___refcolumn)

  # If a schema is given, we only search in that schema, and the returned :table
  # entry is schema qualified as well.
  if schema
    ref_ds = ref_ds.join(:pg_namespace___nsp2, :oid=>:cl2__relnamespace).
      select_more(:nsp2__nspname___schema)
  end

  h = {}
  fklod_map = FOREIGN_KEY_LIST_ON_DELETE_MAP 
  ds.each do |row|
    if r = h[row[:name]]
      r[:columns] << m.call(row[:column])
    else
      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]}
    end
  end
  ref_ds.each do |row|
    r = h[row[:name]]
    r[:table] ||= schema ? SQL::QualifiedIdentifier.new(m.call(row[:schema]), m.call(row[:table])) : m.call(row[:table])
    r[:key] ||= []
    r[:key] << m.call(row[:refcolumn])
  end
  h.values
end
indexes (table, opts=OPTS)

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

[show source] 
# File lib/sequel/adapters/shared/postgres.rb, line 327
def indexes(table, opts=OPTS)
  m = output_identifier_meth
  range = 0...32
  attnums = server_version >= 80100 ? SQL::Function.new(:ANY, :ind__indkey) : range.map{|x| SQL::Subscript.new(:ind__indkey, [x])}
  ds = metadata_dataset.
    from(:pg_class___tab).
    join(:pg_index___ind, :indrelid=>:oid).
    join(:pg_class___indc, :oid=>:indexrelid).
    join(:pg_attribute___att, :attrelid=>:tab__oid, :attnum=>attnums).
    left_join(:pg_constraint___con, :conname=>:indc__relname).
    filter(:indc__relkind=>'i', :ind__indisprimary=>false, :indexprs=>nil, :indpred=>nil, :indisvalid=>true, :tab__oid=>regclass_oid(table, opts)).
    order(:indc__relname, SQL::CaseExpression.new(range.map{|x| [SQL::Subscript.new(:ind__indkey, [x]), x]}, 32, :att__attnum)).
    select(:indc__relname___name, :ind__indisunique___unique, :att__attname___column, :con__condeferrable___deferrable)

  ds.filter!(:indisready=>true, :indcheckxmin=>false) if server_version >= 80300

  indexes = {}
  ds.each do |r|
    i = indexes[m.call(r[:name])] ||= {:columns=>[], :unique=>r[:unique], :deferrable=>r[:deferrable]}
    i[:columns] << m.call(r[:column])
  end
  indexes
end
locks ()

Dataset containing all current database locks

[show source] 
# File lib/sequel/adapters/shared/postgres.rb, line 352
def locks
  dataset.from(:pg_class).join(:pg_locks, :relation=>:relfilenode).select(:pg_class__relname, Sequel::SQL::ColumnAll.new(:pg_locks))
end
notify (channel, opts=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.

[show source] 
# File lib/sequel/adapters/shared/postgres.rb, line 362
def notify(channel, opts=OPTS)
  sql = "NOTIFY "
  dataset.send(:identifier_append, sql, channel)
  if payload = opts[:payload]
    sql << ", "
    dataset.literal_append(sql, payload.to_s)
  end
  execute_ddl(sql, opts)
end
primary_key (table, opts=OPTS)

Return primary key for the given table.

[show source] 
# File lib/sequel/adapters/shared/postgres.rb, line 373
def primary_key(table, opts=OPTS)
  quoted_table = quote_schema_table(table)
  Sequel.synchronize{return @primary_keys[quoted_table] if @primary_keys.has_key?(quoted_table)}
  sql = "#{SELECT_PK_SQL} AND pg_class.oid = #{literal(regclass_oid(table, opts))}"
  value = fetch(sql).single_value
  Sequel.synchronize{@primary_keys[quoted_table] = value}
end
primary_key_sequence (table, opts=OPTS)

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

[show source] 
# File lib/sequel/adapters/shared/postgres.rb, line 382
def primary_key_sequence(table, opts=OPTS)
  quoted_table = quote_schema_table(table)
  Sequel.synchronize{return @primary_key_sequences[quoted_table] if @primary_key_sequences.has_key?(quoted_table)}
  sql = "#{SELECT_SERIAL_SEQUENCE_SQL} AND t.oid = #{literal(regclass_oid(table, opts))}"
  if pks = fetch(sql).single_record
    value = literal(SQL::QualifiedIdentifier.new(pks[:schema], pks[:sequence]))
    Sequel.synchronize{@primary_key_sequences[quoted_table] = value}
  else
    sql = "#{SELECT_CUSTOM_SEQUENCE_SQL} AND t.oid = #{literal(regclass_oid(table, opts))}"
    if pks = fetch(sql).single_record
      value = literal(SQL::QualifiedIdentifier.new(pks[:schema], LiteralString.new(pks[:sequence])))
      Sequel.synchronize{@primary_key_sequences[quoted_table] = value}
    end
  end
end
refresh_view (name, opts=OPTS)

Refresh the materialized view with the given name.

DB.refresh_view(:items_view)
# REFRESH MATERIALIZED VIEW items_view
[show source] 
# File lib/sequel/adapters/shared/postgres.rb, line 402
def refresh_view(name, opts=OPTS)
  run "REFRESH MATERIALIZED VIEW #{quote_schema_table(name)}"
end
reset_conversion_procs ()

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

[show source] 
# File lib/sequel/adapters/shared/postgres.rb, line 408
def reset_conversion_procs
  @conversion_procs = get_conversion_procs
end
reset_primary_key_sequence (table)

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

[show source] 
# File lib/sequel/adapters/shared/postgres.rb, line 414
def reset_primary_key_sequence(table)
  return unless seq = primary_key_sequence(table)
  pk = SQL::Identifier.new(primary_key(table))
  db = self
  seq_ds = db.from(LiteralString.new(seq))
  s, t = schema_and_table(table)
  table = Sequel.qualify(s, t) if s
  get{setval(seq, db[table].select{coalesce(max(pk)+seq_ds.select{:increment_by}, seq_ds.select(:min_value))}, false)}
end
rollback_prepared_transaction (transaction_id)

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

[show source] 
# File lib/sequel/adapters/shared/postgres.rb, line 426
def rollback_prepared_transaction(transaction_id)
  run("ROLLBACK PREPARED #{literal(transaction_id)}")
end
serial_primary_key_options ()

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

[show source] 
# File lib/sequel/adapters/shared/postgres.rb, line 432
def serial_primary_key_options
  {:primary_key => true, :serial => true, :type=>Integer}
end
server_version (server=nil)

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

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

PostgreSQL supports CREATE TABLE IF NOT EXISTS on 9.1+

[show source] 
# File lib/sequel/adapters/shared/postgres.rb, line 454
def supports_create_table_if_not_exists?
  server_version >= 90100
end
supports_deferrable_constraints? ()

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

[show source] 
# File lib/sequel/adapters/shared/postgres.rb, line 459
def supports_deferrable_constraints?
  server_version >= 90000
end
supports_deferrable_foreign_key_constraints? ()

PostgreSQL supports deferrable foreign key constraints.

[show source] 
# File lib/sequel/adapters/shared/postgres.rb, line 464
def supports_deferrable_foreign_key_constraints?
  true
end
supports_drop_table_if_exists? ()

PostgreSQL supports DROP TABLE IF EXISTS

[show source] 
# File lib/sequel/adapters/shared/postgres.rb, line 469
def supports_drop_table_if_exists?
  true
end
supports_partial_indexes? ()

PostgreSQL supports partial indexes.

[show source] 
# File lib/sequel/adapters/shared/postgres.rb, line 474
def supports_partial_indexes?
  true
end
supports_prepared_transactions? ()

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

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

PostgreSQL supports savepoints

[show source] 
# File lib/sequel/adapters/shared/postgres.rb, line 486
def supports_savepoints?
  true
end
supports_transaction_isolation_levels? ()

PostgreSQL supports transaction isolation levels

[show source] 
# File lib/sequel/adapters/shared/postgres.rb, line 491
def supports_transaction_isolation_levels?
  true
end
supports_transactional_ddl? ()

PostgreSQL supports transaction DDL statements.

[show source] 
# File lib/sequel/adapters/shared/postgres.rb, line 496
def supports_transactional_ddl?
  true
end
tables (opts=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:

: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

[show source] 
# File lib/sequel/adapters/shared/postgres.rb, line 509
def tables(opts=OPTS, &block)
  pg_class_relname('r', opts, &block)
end
type_supported? (type)

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

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

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

[show source] 
# File lib/sequel/adapters/shared/postgres.rb, line 527
def views(opts=OPTS)
  pg_class_relname('v', opts)
end