DROP EXTENSION removes extensions from the database. Dropping an extension causes its component objects to be dropped as well.
You must own the extension to use DROP EXTENSION.
Do not throw an error if the extension does not exist. A notice is issued in this case.
The name of an installed extension.
Automatically drop objects that depend on the extension, and in turn all objects that depend on those objects (see Section 5.13).
Refuse to drop the extension if any objects depend on it (other than its own member objects and other extensions listed in the same DROP command). This is the default.
To remove the extension hstore from the current database:
DROP EXTENSION hstore;
This command will fail if any of hstore's objects are in use in the database, for example if any tables have columns of the hstore type. Add the CASCADE option to forcibly remove those dependent objects as well.