In the last two recipes, we showed you how to install external modules in PostgreSQL to augment its capabilities.
In this recipe, we will show you some more capabilities offered by the extension infrastructure.
How to do it...
First, we list all the available extensions:
postgres=# \x on
Expanded display is on.
postgres=# SELECT *
postgres-# FROM pg_available_extensions
postgres-# ORDER BY name;
-[ RECORD 1 ]-----+--------------------------------------------------
name | adminpack
default_version | 1.0
installed_version |
comment | administrative functions for PostgreSQL
-[ RECORD 2 ]-----+--------------------------------------------------
name | autoinc
default_version | 1.0
installed_version |
comment | functions for autoincrementing fields
(...)
In particular, if the dblink extension is installed, then we see...