Re: describe objects, as in pg_depend

Alvaro Herrera <alvherre@alvh.no-ip.org> writes:
> A customer of ours (Enova Financial) requested the ability to describe
> objects in pg_depend.  The wiki contains a simplistic SQL snippet that
> does the task, but only for some of the object types, and it's rather
> ugly.  It struck me that we could fulfill this very easily by exposing
> the getObjectDescription() function at the SQL level, as in the attached
> module.

What's the point of the InvalidOid check?  It seems like you're mostly
just introducing a corner case: sometimes, but not always, the function
will return NULL instead of failing for bad input.  I think it should
just fail always.
        regards, tom lane