Add current_database().

Add current_database().

> Quick system function to pull out the current database.
>
> I've used this a number of times to allow stored procedures to find out
> where they are.  Especially useful for those that do logging or hit a
> remote server.
>
> It's called current_database() to match with current_user().

It's also a necessity for an informational schema.  The catalog
(database) name is required in a number of places.

Rod Taylor