below) while creating a trigger.
+ Each of the groups of functions described below is provided as a
+ separately-installable extension.
+
+
-
refint<span class="marked">.c</span> — Functions for Implementing Referential Integrity
+
refint — Functions for Implementing Referential Integrity
check_primary_key() and
-
timetravel<span class="marked">.c</span> — Functions for Implementing Time Travel
+
timetravel — Functions for Implementing Time Travel
Long ago,
PostgreSQL had a built-in time travel feature
-
autoinc<span class="marked">.c</span> — Functions for Autoincrementing Fields
+
autoinc — Functions for Autoincrementing Fields
autoinc() is a trigger that stores the next value of
-
insert_username<span class="marked">.c</span> — Functions for Tracking Who Changed a Table
+
insert_username — Functions for Tracking Who Changed a Table
insert_username() is a trigger that stores the current
-
moddatetime<span class="marked">.c</span> — Functions for Tracking Last Modification Time
+
moddatetime — Functions for Tracking Last Modification Time
moddatetime() is a trigger that stores the current
Many modules supply new user-defined functions, operators, or types.
To make use of one of these modules, after you have installed the code
- you need to register the new objects in the database
- system by running the SQL commands in the .sql file
- supplied by the module. For example,
+ you need to register the new SQL objects in the database system.
+ In
PostgreSQL 9.1 and later, this is done by executing+ a command. In a fresh database,
+ you can simply do
-psql -d dbname -f SHAREDIR/contrib/module.sql
+CREATE EXTENSION module_name;
- Here, SHAREDIR means the installation's share
- directory (pg_config --sharedir will tell you what this is).
- In most cases the script must be run by a database superuser.
-
-
- You need to run the .sql file in each database that you want
+ This command must be run by a database superuser. This registers the
+ new SQL objects in the current database only, so you need to run this
+ command in each database that you want
the module's facilities to be available in. Alternatively, run it in
- database template1 so that the module will be copied into
+ database template1 so that the extension will be copied into
subsequently-created databases by default.
- You can modify the first command in the .sql file to determine
- which schema within the database the module's objects will be created in.
- By default, they will be placed in public.
+ Many modules allow you to install their objects in a schema of your
+ choice. To do that, add SCHEMA
+ schema_name to the CREATE EXTENSION
+ command. By default, the objects will be placed in your current creation
+ target schema, typically public.
- After a major-version upgrade of
PostgreSQL, run the- installation script again, even though the module's objects might have
- been brought forward from the old installation by dump and restore.
- This ensures that any new functions will be available and any needed
- corrections will be applied.
+ If your database was brought forward by dump and reload from a pre-9.1
+ version of
PostgreSQL, and you had been using the pre-9.1+ version of the module in it, you should instead do
+
+CREATE EXTENSION module_name FROM unpackaged;
+
+
+ This will update the pre-9.1 objects of the module into a proper
+ extension object. Future updates to the module will be
+ managed by .
+ For more information about extension updates, see
+ .
&adminpack;
Usage
- Running the installation script creates a text search template
- intdict_template and a dictionary intdict
+ Installing the dict_int extension creates a text search
+ template intdict_template and a dictionary intdict
based on it, with the default parameters. You can alter the
parameters, for example
Usage
- Running the installation script creates a text search template
- xsyn_template and a dictionary xsyn
+ Installing the dict_xsyn extension creates a text search
+ template xsyn_template and a dictionary xsyn
based on it, with default parameters. You can alter the
parameters, for example
The earthdistance module provides two different approaches to
calculating great circle distances on the surface of the Earth. The one
- described first depends on the cube package (which
+ described first depends on the cube module (which
must be installed before earthdistance can be
installed). The second one is based on the built-in point data type,
using longitude and latitude for the coordinates.
Compatibility
- When upgrading from older versions, always load the new
- version of this module into the database before restoring a dump.
- Otherwise, many new features will be unavailable.
-
-
As of PostgreSQL 9.0, hstore uses a different internal
representation than previous versions. This presents no obstacle for
This view, and the function pg_stat_statements_reset,
are available only in databases they have been specifically installed into
- by running the pg_stat_statements.sql install script.
+ by installing the pg_stat_statements extension.
However, statistics are tracked across all databases of the server
whenever the pg_stat_statements module is loaded
into the server, regardless of presence of the view.
Create a composite type describing the desired output columns,
- similar to the examples in the installation script. Then define a
+ similar to the examples in
+ contrib/tablefunc/tablefunc--1.0.sql.
+ Then define a
unique function name accepting one text parameter and returning
setof your_type_name, but linking to the same underlying
crosstab C function. For example, if your source data
Usage
- Running the installation script creates a text search parser
- testparser. It has no user-configurable parameters.
+ Installing the test_parser extension creates a text search
+ parser testparser. It has no user-configurable parameters.
before loading the dump data! If your old installation
had the
tsearch2 objects in a schema other than public, be sure to adjust the
- <literal>tsearch2 installation script so that the replacement
+ <command>CREATE EXTENSION command so that the replacement
objects are created in that same schema.
Usage
- Running the installation script unaccent.sql creates a text
+ Installing the unaccent extension creates a text
search template unaccent and a dictionary unaccent
based on it. The unaccent dictionary has the default
parameter setting RULES='unaccent', which makes it immediately
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