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Sequel::Postgres::DatabaseMethods

Methods shared by Database instances that connect to PostgreSQL.

Constants

DATABASE_ERROR_REGEXPS
EXCLUDE_SCHEMAS
EXCLUSION_CONSTRAINT_SQL_STATE
FOREIGN_KEY_LIST_ON_DELETE_MAP
POSTGRES_DEFAULT_RE
PREPARED_ARG_PLACEHOLDER
RE_CURRVAL_ERROR
SELECT_CUSTOM_SEQUENCE_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

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

SQL fragment for getting sequence associated with table's primary key, assuming it was a serial primary key column.

SYSTEM_TABLE_REGEXP
UNLOGGED
VALID_CLIENT_MIN_MESSAGES

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) click to toggle source

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

# File lib/sequel/adapters/shared/postgres.rb, line 158
def commit_prepared_transaction(transaction_id)
  run("COMMIT PREPARED #{literal(transaction_id)}")
end
create_function(name, definition, opts={}) click to toggle source

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.

# File lib/sequel/adapters/shared/postgres.rb, line 182
def create_function(name, definition, opts={})
  self << create_function_sql(name, definition, opts)
end
create_language(name, opts={}) click to toggle source

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.

# File lib/sequel/adapters/shared/postgres.rb, line 193
def create_language(name, opts={})
  self << create_language_sql(name, opts)
end
create_schema(name) click to toggle source

Create a schema in the database. Arguments:

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

# File lib/sequel/adapters/shared/postgres.rb, line 199
def create_schema(name)
  self << create_schema_sql(name)
end
create_trigger(table, name, function, opts={}) click to toggle source

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.

# File lib/sequel/adapters/shared/postgres.rb, line 213
def create_trigger(table, name, function, opts={})
  self << create_trigger_sql(table, name, function, opts)
end
database_type() click to toggle source

PostgreSQL uses the :postgres database type.

# File lib/sequel/adapters/shared/postgres.rb, line 218
def database_type
  :postgres
end
do(code, opts={}) click to toggle source

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.

# File lib/sequel/adapters/shared/postgres.rb, line 227
def do(code, opts={})
  language = opts[:language]
  run "DO #{"LANGUAGE #{literal(language.to_s)} " if language}#{literal(code)}"
end
drop_function(name, opts={}) click to toggle source

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.

# File lib/sequel/adapters/shared/postgres.rb, line 238
def drop_function(name, opts={})
  self << drop_function_sql(name, opts)
end
drop_language(name, opts={}) click to toggle source

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.

# File lib/sequel/adapters/shared/postgres.rb, line 247
def drop_language(name, opts={})
  self << drop_language_sql(name, opts)
end
drop_schema(name, opts={}) click to toggle source

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.

# File lib/sequel/adapters/shared/postgres.rb, line 256
def drop_schema(name, opts={})
  self << drop_schema_sql(name, opts)
end
drop_trigger(table, name, opts={}) click to toggle source

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.

# File lib/sequel/adapters/shared/postgres.rb, line 266
def drop_trigger(table, name, opts={})
  self << drop_trigger_sql(table, name, opts)
end
foreign_key_list(table, opts={}) click to toggle source

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

# File lib/sequel/adapters/shared/postgres.rb, line 272
def foreign_key_list(table, 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={}) click to toggle source

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

# File lib/sequel/adapters/shared/postgres.rb, line 326
def indexes(table, 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() click to toggle source

Dataset containing all current database locks

# File lib/sequel/adapters/shared/postgres.rb, line 351
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={}) click to toggle source

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.

# File lib/sequel/adapters/shared/postgres.rb, line 361
def notify(channel, 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={}) click to toggle source

Return primary key for the given table.

# File lib/sequel/adapters/shared/postgres.rb, line 372
def primary_key(table, 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={}) click to toggle source

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

# File lib/sequel/adapters/shared/postgres.rb, line 381
def primary_key_sequence(table, 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
reset_conversion_procs() click to toggle source

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

# File lib/sequel/adapters/shared/postgres.rb, line 399
def reset_conversion_procs
  @conversion_procs = get_conversion_procs
end
reset_primary_key_sequence(table) click to toggle source

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

# File lib/sequel/adapters/shared/postgres.rb, line 405
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) click to toggle source

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

# File lib/sequel/adapters/shared/postgres.rb, line 417
def rollback_prepared_transaction(transaction_id)
  run("ROLLBACK PREPARED #{literal(transaction_id)}")
end
serial_primary_key_options() click to toggle source

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

# File lib/sequel/adapters/shared/postgres.rb, line 423
def serial_primary_key_options
  {:primary_key => true, :serial => true, :type=>Integer}
end
server_version(server=nil) click to toggle source

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

# File lib/sequel/adapters/shared/postgres.rb, line 428
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?() click to toggle source

PostgreSQL supports CREATE TABLE IF NOT EXISTS on 9.1+

# File lib/sequel/adapters/shared/postgres.rb, line 445
def supports_create_table_if_not_exists?
  server_version >= 90100
end
supports_deferrable_constraints?() click to toggle source

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

# File lib/sequel/adapters/shared/postgres.rb, line 450
def supports_deferrable_constraints?
  server_version >= 90000
end
supports_deferrable_foreign_key_constraints?() click to toggle source

PostgreSQL supports deferrable foreign key constraints.

# File lib/sequel/adapters/shared/postgres.rb, line 455
def supports_deferrable_foreign_key_constraints?
  true
end
supports_drop_table_if_exists?() click to toggle source

PostgreSQL supports DROP TABLE IF EXISTS

# File lib/sequel/adapters/shared/postgres.rb, line 460
def supports_drop_table_if_exists?
  true
end
supports_prepared_transactions?() click to toggle source

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

# File lib/sequel/adapters/shared/postgres.rb, line 466
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?() click to toggle source

PostgreSQL supports savepoints

# File lib/sequel/adapters/shared/postgres.rb, line 472
def supports_savepoints?
  true
end
supports_transaction_isolation_levels?() click to toggle source

PostgreSQL supports transaction isolation levels

# File lib/sequel/adapters/shared/postgres.rb, line 477
def supports_transaction_isolation_levels?
  true
end
supports_transactional_ddl?() click to toggle source

PostgreSQL supports transaction DDL statements.

# File lib/sequel/adapters/shared/postgres.rb, line 482
def supports_transactional_ddl?
  true
end
tables(opts={}, &block) click to toggle source

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

# File lib/sequel/adapters/shared/postgres.rb, line 495
def tables(opts={}, &block)
  pg_class_relname('r', opts, &block)
end
type_supported?(type) click to toggle source

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

# File lib/sequel/adapters/shared/postgres.rb, line 501
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={}) click to toggle source

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

# File lib/sequel/adapters/shared/postgres.rb, line 513
def views(opts={})
  pg_class_relname('v', opts)
end

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