Class: ActiveRecord::ConnectionAdapters::PostgreSQLAdapter

Files

activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb

Parent

Description

The PostgreSQL adapter works both with the native C (ruby.scripting.ca/postgres/) and the pure Ruby (available both as gem and from rubyforge.org/frs/?group_id=234&release_id=1944) drivers.

Options:

:host - Defaults to "localhost".
:port - Defaults to 5432.
:username - Defaults to nothing.
:password - Defaults to nothing.
:database - The name of the database. No default, must be provided.
:schema_search_path - An optional schema search path for the connection given as a string of comma-separated schema names. This is backward-compatible with the :schema_order option.
:encoding - An optional client encoding that is used in a SET client_encoding TO <encoding> call on the connection.
:min_messages - An optional client min messages that is used in a SET client_min_messages TO <min_messages> call on the connection.
:allow_concurrency - If true, use async query methods so Ruby threads don‘t deadlock; otherwise, use blocking query methods.

Methods

Constants

ADAPTER_NAME

'PostgreSQL'.freeze

NATIVE_DATABASE_TYPES

{ :primary_key => "serial primary key".freeze, :string => { :name => "character varying", :limit => 255 }, :text => { :name => "text" }, :integer => { :name => "integer" }, :float => { :name => "float" }, :decimal => { :name => "decimal" }, :datetime => { :name => "timestamp" }, :timestamp => { :name => "timestamp" }, :time => { :name => "time" }, :date => { :name => "date" }, :binary => { :name => "bytea" }, :boolean => { :name => "boolean" }

PQTRANS_IDLE

defined?(PGconn::PQTRANS_IDLE) ? PGconn::PQTRANS_IDLE : 0 ruby-pg defines Ruby constants for transaction status, ruby-postgres does not.

Public Class methods

new (connection, logger, connection_parameters, config)

Initializes and connects a PostgreSQL adapter.

Public Instance methods

active? ()

Is this connection alive and ready for queries?

adapter_name ()

Returns ‘PostgreSQL’ as adapter name for identification purposes.

add_column (table_name, column_name, type, options = {})

Adds a new column to the named table. See TableDefinition#column for details of the options you can use.

begin_db_transaction ()

Begins a transaction.

change_column (table_name, column_name, type, options = {})

Changes the column of a table.

change_column_default (table_name, column_name, default)

Changes the default value of a table column.

change_column_null (table_name, column_name, null, default = nil)

client_min_messages ()

Returns the current client message level.

client_min_messages= (level)

Set the client message level.

columns (table_name, name = nil)

Returns the list of all column definitions for a table.

commit_db_transaction ()

Commits a transaction.

create_database (name, options = {})

Create a new PostgreSQL database. Options include :owner, :template, :encoding, :tablespace, and :connection_limit (note that MySQL uses :charset while PostgreSQL uses :encoding).

Example:

  create_database config[:database], config
  create_database 'foo_development', :encoding => 'unicode'

current_database ()

Returns the current database name.

disconnect! ()

Close the connection.

encoding ()

Returns the current database encoding format.

escape_bytea (value)

Escapes binary strings for bytea input to the database.

execute (sql, name = nil)

Executes an SQL statement, returning a PGresult object on success or raising a PGError exception otherwise.

indexes (table_name, name = nil)

Returns the list of all indexes for a table.

insert (sql, name = nil, pk = nil, id_value = nil, sequence_name = nil)

Executes an INSERT query and returns the new record‘s ID

reconnect! ()

Close then reopen the connection.

remove_index (table_name, options = {})

Drops an index from a table.

rename_column (table_name, column_name, new_column_name)

Renames a column in a table.

rename_table (name, new_name)

Renames a table.

rollback_db_transaction ()

Aborts a transaction.

schema_search_path ()

Returns the active schema search path.

schema_search_path= (schema_csv)

Sets the schema search path to a string of comma-separated schema names. Names beginning with $ have to be quoted (e.g. $user => ’$user’). See: www.postgresql.org/docs/current/static/ddl-schemas.html

This should be not be called manually but set in database.yml.

select_rows (sql, name = nil)

Executes a SELECT query and returns an array of rows. Each row is an array of field values.

tables (name = nil)

Returns the list of all tables in the schema search path or a specified schema.

transaction (start_db_transaction = true) {|| ...}

Wrap a block in a transaction. Returns result of block.

transaction_active? ()

Check whether a transaction is active.

type_to_sql (type, limit = nil, precision = nil, scale = nil)

Maps logical Rails types to PostgreSQL-specific data types.

unescape_bytea (value)

Unescapes bytea output from a database to the binary string it represents. NOTE: This is NOT an inverse of escape_bytea! This is only to be used

      on escaped binary output from database drive.

ActiveRecord::ConnectionAdapters::PostgreSQLAdapter