CREATE EXTENSION(7) PostgreSQL 9.6.7 Documentation CREATE EXTENSION(7)
NAME
CREATE_EXTENSION - install an extension
SYNOPSIS
CREATE EXTENSION [ IF NOT EXISTS ] extension_name
[ WITH ] [ SCHEMA schema_name ]
[ VERSION version ]
[ FROM old_version ]
[ CASCADE ]
DESCRIPTION
CREATE EXTENSION loads a new extension into the current database. There
must not be an extension of the same name already loaded.
Loading an extension essentially amounts to running the extension's
script file. The script will typically create new SQL objects such as
functions, data types, operators and index support methods. CREATE
EXTENSION additionally records the identities of all the created
objects, so that they can be dropped again if DROP EXTENSION is issued.
Loading an extension requires the same privileges that would be
required to create its component objects. For most extensions this
means superuser or database owner privileges are needed. The user who
runs CREATE EXTENSION becomes the owner of the extension for purposes
of later privilege checks, as well as the owner of any objects created
by the extension's script.
PARAMETERS
IF NOT EXISTS
Do not throw an error if an extension with the same name already
exists. A notice is issued in this case. Note that there is no
guarantee that the existing extension is anything like the one that
would have been created from the currently-available script file.
extension_name
The name of the extension to be installed. PostgreSQL will create
the extension using details from the file
SHAREDIR/extension/extension_name.control.
schema_name
The name of the schema in which to install the extension's objects,
given that the extension allows its contents to be relocated. The
named schema must already exist. If not specified, and the
extension's control file does not specify a schema either, the
current default object creation schema is used.
If the extension specifies a schema parameter in its control file,
then that schema cannot be overridden with a SCHEMA clause.
Normally, an error will be raised if a SCHEMA clause is given and
it conflicts with the extension's schema parameter. However, if the
CASCADE clause is also given, then schema_name is ignored when it
conflicts. The given schema_name will be used for installation of
any needed extensions that do not specify schema in their control
files.
Remember that the extension itself is not considered to be within
any schema: extensions have unqualified names that must be unique
database-wide. But objects belonging to the extension can be within
schemas.
version
The version of the extension to install. This can be written as
either an identifier or a string literal. The default version is
whatever is specified in the extension's control file.
old_version
FROM old_version must be specified when, and only when, you are
attempting to install an extension that replaces an "old style"
module that is just a collection of objects not packaged into an
extension. This option causes CREATE EXTENSION to run an
alternative installation script that absorbs the existing objects
into the extension, instead of creating new objects. Be careful
that SCHEMA specifies the schema containing these pre-existing
objects.
The value to use for old_version is determined by the extension's
author, and might vary if there is more than one version of the
old-style module that can be upgraded into an extension. For the
standard additional modules supplied with pre-9.1 PostgreSQL, use
unpackaged for old_version when updating a module to extension
style.
CASCADE
Automatically install any extensions that this extension depends on
that are not already installed. Their dependencies are likewise
automatically installed, recursively. The SCHEMA clause, if given,
applies to all extensions that get installed this way. Other
options of the statement are not applied to automatically-installed
extensions; in particular, their default versions are always
selected.
NOTES
Before you can use CREATE EXTENSION to load an extension into a
database, the extension's supporting files must be installed.
Information about installing the extensions supplied with PostgreSQL
can be found in Additional Supplied Modules.
The extensions currently available for loading can be identified from
the pg_available_extensions or pg_available_extension_versions system
views.
For information about writing new extensions, see Section 36.15,
"Packaging Related Objects into an Extension", in the documentation.
EXAMPLES
Install the hstore extension into the current database:
CREATE EXTENSION hstore;
Update a pre-9.1 installation of hstore into extension style:
CREATE EXTENSION hstore SCHEMA public FROM unpackaged;
Be careful to specify the schema in which you installed the existing
hstore objects.
COMPATIBILITY
CREATE EXTENSION is a PostgreSQL extension.
SEE ALSO
ALTER EXTENSION (ALTER_EXTENSION(7)), DROP EXTENSION
(DROP_EXTENSION(7))
PostgreSQL 9.6.7 2018 CREATE EXTENSION(7)
postgresql 9.6.7 - Generated Fri Feb 9 08:18:04 CST 2018