Renaming a constraint

Started by Csaba Nagyabout 18 years ago5 messagesgeneral
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#1Csaba Nagy
nagy@ecircle-ag.com

I found an old post regarding the subject, where modifying the
pg_constraint entry was recommended:

http://archives.postgresql.org/pgsql-admin/2003-04/msg00339.php

Is this still safe to do ? The pertinent docs don't say anything pro or
contra:
http://www.postgresql.org/docs/8.2/static/catalog-pg-constraint.html

I need to rename a few constraints to keep our schema logically
consistent. It would be of course nice to have an ALTER TABLE option to
do it, but if updating pg_constraint is safe it would do it for now.

Thanks,
Csaba.

#2Tom Lane
tgl@sss.pgh.pa.us
In reply to: Csaba Nagy (#1)
Re: Renaming a constraint

Csaba Nagy <nagy@ecircle-ag.com> writes:

I found an old post regarding the subject, where modifying the
pg_constraint entry was recommended:

http://archives.postgresql.org/pgsql-admin/2003-04/msg00339.php

Is this still safe to do ?

What kind of constraint?

regards, tom lane

#3Csaba Nagy
nagy@ecircle-ag.com
In reply to: Tom Lane (#2)
Re: Renaming a constraint

On Tue, 2008-02-05 at 12:11 -0500, Tom Lane wrote:

Csaba Nagy <nagy@ecircle-ag.com> writes:

I found an old post regarding the subject, where modifying the
pg_constraint entry was recommended:

http://archives.postgresql.org/pgsql-admin/2003-04/msg00339.php

Is this still safe to do ?

What kind of constraint?

The only ones left are foreign key constraints. I had a few not nulls
too, but those are not actually there anyway (see my other post).

Thanks,
Csaba.

#4Tom Lane
tgl@sss.pgh.pa.us
In reply to: Csaba Nagy (#3)
Re: Renaming a constraint

Csaba Nagy <nagy@ecircle-ag.com> writes:

On Tue, 2008-02-05 at 12:11 -0500, Tom Lane wrote:

Csaba Nagy <nagy@ecircle-ag.com> writes:

Is this still safe to do ?

What kind of constraint?

The only ones left are foreign key constraints. I had a few not nulls
too, but those are not actually there anyway (see my other post).

IIRC, the name of an FK constraint also appears in the arguments for its
triggers. If you didn't update those too, the behavior might be a bit
inconsistent, depending on which PG version you're using. In particular
I'm not sure which name pg_dump will believe.

regards, tom lane

#5Csaba Nagy
nagy@ecircle-ag.com
In reply to: Tom Lane (#4)
Re: Renaming a constraint

On Wed, 2008-02-06 at 11:03 -0500, Tom Lane wrote:

IIRC, the name of an FK constraint also appears in the arguments for its
triggers. If you didn't update those too, the behavior might be a bit
inconsistent, depending on which PG version you're using. In particular
I'm not sure which name pg_dump will believe.

OK, I think I'll just give up on renaming them.

How hard would be to implement renaming constraints as an alter table
option ? It sounds to me like it should be a task requiring mostly
legwork than programming skills, would it be good task for a beginner in
C like me ? If it is at all regarded as a needed feature...

Thanks,
Csaba.