PostgreSQL has many features not touched upon in this tutorial introduction, which has been oriented toward newer users of SQL. These features are discussed in more detail in the remainder of this book. If you feel you need more introductory material, please visit the PostgreSQL web site for links to more resources. Prev Next Inheritance Up The SQL Language

The pg_available_extension_versions view lists the specific extension versions that are available for installation. See also the pg_extension catalog, which shows the extensions currently installed. Table 50-60. pg_available_extension_versions Columns Name Type Description name name Extension name version text Version name installed bool True if this version of this extension is currently installed superuser bool True if only superusers are allowed to install this extension relocatable bool T

Here we give a short overview of the stages a query has to pass in order to obtain a result. A connection from an application program to the PostgreSQL server has to be established. The application program transmits a query to the server and waits to receive the results sent back by the server. The parser stage checks the query transmitted by the application program for correct syntax and creates a query tree. The rewrite system takes the query tree created by the parser stage and looks f

NameCREATE TABLE -- define a new table Synopsis CREATE [ [ GLOBAL | LOCAL ] { TEMPORARY | TEMP } | UNLOGGED ] TABLE [ IF NOT EXISTS ] table_name ( [ { column_name data_type [ COLLATE collation ] [ column_constraint [ ... ] ] | table_constraint | LIKE source_table [ like_option ... ] } [, ... ] ] ) [ INHERITS ( parent_table [, ... ] ) ] [ WITH ( storage_parameter [= value] [, ... ] ) | WITH OIDS | WITHOUT OIDS ] [ ON COMMIT { PRESERVE ROWS | DELETE ROWS | DROP } ] [ TABLESPAC

NameCREATE TRIGGER -- define a new trigger Synopsis CREATE [ CONSTRAINT ] TRIGGER name { BEFORE | AFTER | INSTEAD OF } { event [ OR ... ] } ON table_name [ FROM referenced_table_name ] [ NOT DEFERRABLE | [ DEFERRABLE ] [ INITIALLY IMMEDIATE | INITIALLY DEFERRED ] ] [ FOR [ EACH ] { ROW | STATEMENT } ] [ WHEN ( condition ) ] EXECUTE PROCEDURE function_name ( arguments ) where event can be one of: INSERT UPDATE [ OF column_name [, ... ] ] DELETE TRU

NameDROP FOREIGN TABLE -- remove a foreign table Synopsis DROP FOREIGN TABLE [ IF EXISTS ] name [, ...] [ CASCADE | RESTRICT ] Description DROP FOREIGN TABLE removes a foreign table. Only the owner of a foreign table can remove it. Parameters IF EXISTS Do not throw an error if the foreign table does not exist. A notice is issued in this case. name The name (optionally schema-qualified) of the foreign table to drop. CASCADE Automatically drop objects that depend on the foreign

NameALTER DOMAIN -- change the definition of a domain Synopsis ALTER DOMAIN name { SET DEFAULT expression | DROP DEFAULT } ALTER DOMAIN name { SET | DROP } NOT NULL ALTER DOMAIN name ADD domain_constraint [ NOT VALID ] ALTER DOMAIN name DROP CONSTRAINT [ IF EXISTS ] constraint_name [ RESTRICT | CASCADE ] ALTER DOMAIN name RENAME CONSTRAINT constraint_name TO new_constraint_name ALTER DOMAIN name VALIDATE CONSTRAINT constraint_name ALTER DOMAIN name OWNER TO {

PostgreSQL supports a powerful rule system for the specification of views and ambiguous view updates. Originally the PostgreSQL rule system consisted of two implementations: The first one worked using row level processing and was implemented deep in the executor. The rule system was called whenever an individual row had been accessed. This implementation was removed in 1995 when the last official release of the Berkeley Postgres project was transformed into Postgres95. The second implementat

standby_mode (boolean) Specifies whether to start the PostgreSQL server as a standby. If this parameter is on, the server will not stop recovery when the end of archived WAL is reached, but will keep trying to continue recovery by fetching new WAL segments using restore_command and/or by connecting to the primary server as specified by the primary_conninfo setting. primary_conninfo (string) Specifies a connection string to be used for the standby server to connect with the primary. This s

btree_gist provides GiST index operator classes that implement B-tree equivalent behavior for the data types int2, int4, int8, float4, float8, numeric, timestamp with time zone, timestamp without time zone, time with time zone, time without time zone, date, interval, oid, money, char, varchar, text, bytea, bit, varbit, macaddr, inet, and cidr. In general, these operator classes will not outperform the equivalent standard B-tree index methods, and they lack one major feature of the standard B-tr