Re: [v9.2] DROP Reworks Part.0 - 'missing_ok' support of get_object_address

On Tue, Jun 14, 2011 at 8:06 AM, Kohei KaiGai <kaigai@kaigai.gr.jp> wrote:
> The attached patch is a preparation to rework implementation of DROP statement
> using a common code. That intends to apply get_object_address() to resolve name
> of objects to be removed, and eventually minimizes the number of places to put
> permission checks.
>
> Its first step is an enhancement of get_object_address; to accept 'missing_ok'
> argument to handle cases when IF EXISTS clause is supplied.
> If 'missing_ok' was true and the supplied name was not found, the patched
> get_object_address() returns an ObjectAddress with InvalidOid as objectId.
> If 'missing_ok' was false, its behavior is not changed.

Let's consistently make missing_ok the last argument to all of the
functions to which we're adding it.

I don't think it's a good idea for get_relation_by_qualified_name() to
be second-guessing the error message that RangeVarGetRelid() feels
like throwing.

I think that attempting to fetch the column foo.bar when foo doesn't
exist should be an error even if missing_ok is true.  I believe that's
consistent with what we do elsewhere.  (If it *were* necessary to open
the relation without failing if it's not there, you could use
try_relation_openrv instead of doing as you've done here.)

There is certainly a more compact way of writing the logic in
get_object_address_typeobj.  Also, I think that function should be
called get_object_address_type(); the "obj" on the end seems
redundant.

Apart from those comments this looks pretty sensible.

-- 
Robert Haas
EnterpriseDB: http://www.enterprisedb.com
The Enterprise PostgreSQL Company