CREATE EXTENSION — install an extension
CREATE EXTENSION [ IF NOT EXISTS ]
extension_name[ WITH ] [ SCHEMA
schema_name] [ VERSION
version] [ FROM
old_version] [ CASCADE ]
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
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
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
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.
The name of the extension to be installed. PostgreSQL will create the extension using
details from the file
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
parameter in its control file, then that schema cannot be
overridden with a
Normally, an error will be raised if a
SCHEMA clause is given and it conflicts with the
schema parameter. However,
CASCADE clause is also given,
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.
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 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
old_version when updating a module
to extension style.
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.
Before you can use
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
For information about writing new extensions, see Section 37.15.
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
CREATE EXTENSION is a PostgreSQL extension.
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