Re: the case for machine-readable error fields

Sam Mason <sam@samason.me.uk> writes:
> On Wed, Aug 05, 2009 at 12:41:30PM -0500, Kevin Grittner wrote:
>> Anyway, it was a bad suggestion that we provide a way to specify a
>> SQLSTATE to use for a constraint failure.  I do think that some field
>> which could be used for that purpose would be good.  Preferably
>> something which could be specified in the declaration of the
>> constraint.

> I still stand by my assertion that the constraint name is sufficient for
> the original purpose.

Yeah.  Changing the SQLSTATE for a given error seems much more likely
to break things than to be helpful.  It does make sense to be able to
extract the constraint name for a constraint-related error without
having to make unsafe assumptions about the spelling of the
human-readable error message, though.

Peter pointed out upthread that the SQL standard already calls out some
things that should be available in this way --- has anyone studied that
yet?
        regards, tom lane