Provided by: postgresql-client-9.1_9.1.3-2_i386 bug


       CREATE_EXTENSION - install an extension


       CREATE EXTENSION [ IF NOT EXISTS ] extension_name
           [ WITH ] [ SCHEMA schema ]
                    [ VERSION version ]
                    [ FROM old_version ]


       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.


           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.

           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.

           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

           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


       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

       For information about writing new extensions, see Section 35.15,
       "Packaging Related Objects into an Extension", in the documentation.


       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.


       CREATE EXTENSION is a PostgreSQL extension.