Robert Haas <robertmhaas@gmail.com> writes:
> On Tue, Mar 23, 2010 at 8:16 PM, Tom Lane <tgl@sss.pgh.pa.us> wrote:
>> My first thought about a catalog representation would be to add a column
>> to pg_auth which is a DB OID for local users or zero for global users.
>> However, you'd probably want to prevent local users and global users
>> from having the same names, and it's not very clear how to do that
>> with this representation (though that'd be even worse with separate
>> catalogs). �I guess we could fall back on a creation-time check (ick).
> Could we use a suitably defined exclusion constraint?
Not unless you'd like to solve the issues with triggers on system
catalogs first ...
regards, tom lane
