Horton

Re: cataloguing NOT NULL constraints

Peter Eisentraut <peter.eisentraut@enterprisedb.com>

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From: Peter Eisentraut <peter.eisentraut@enterprisedb.com>
To: Alvaro Herrera <alvherre@alvh.no-ip.org>, Amit Langote <amitlangote09@gmail.com>
Cc: Laurenz Albe <laurenz.albe@cybertec.at>, Pg Hackers <pgsql-hackers@lists.postgresql.org>
Date: 2022-09-14T20:03:50Z
Lists: pgsql-hackers

Commits

Same data as JSON: GET /api/v1/messages/:b64id/commits the thread's linked commits as JSON, with link sources. API reference →

  1. Revert structural changes to not-null constraints

  2. Fix inconsistencies in error messages

  3. Disallow direct change of NO INHERIT of not-null constraints

  4. Disallow NO INHERIT not-null constraints on partitioned tables

  5. Better handle indirect constraint drops

  6. Don't try to assign smart names to constraints

  7. Fix restore of not-null constraints with inheritance

  8. ATTACH PARTITION: Don't match a PK with a UNIQUE constraint

  9. Fix propagating attnotnull in multiple inheritance

  10. Check stack depth in new recursive functions

  11. Move privilege check to the right place

  12. Update information_schema definition for not-null constraints

  13. Fix not-null constraint test

  14. Disallow changing NO INHERIT status of a not-null constraint

  15. Catalog not-null constraints

  16. parallel_schedule: add comment on event_trigger test dependency

  17. Revert "Catalog NOT NULL constraints" and fallout

  18. Adjust contrib/sepgsql regression test expected outputs.

  19. Fix table name clash in recently introduced test

  20. Catalog NOT NULL constraints

  21. Change the rules for inherited CHECK constraints to be essentially the same

On 09.09.22 19:58, Alvaro Herrera wrote:
> There were a lot more problems in that submission than I at first
> realized, and I had to rewrite a lot of code in order to fix them.  I
> have fixed all the user-visible problems I found in this version, and
> reviewed the tests results more carefully so I am now more confident
> that behaviourally it's doing the right thing; but

Reading through the SQL standard again, I think this patch goes a bit 
too far in folding NOT NULL and CHECK constraints together.  The spec 
says that you need to remember whether a column was defined as NOT NULL, 
and that the commands DROP NOT NULL and SET NOT NULL only affect 
constraints defined in that way.  In this implementation, a constraint 
defined as NOT NULL is converted to a CHECK (x IS NOT NULL) constraint 
and the original definition is forgotten.

Besides that, I think that users are not going to like that pg_dump 
rewrites their NOT NULL constraints into CHECK table constraints.

I suspect that this needs a separate contype for NOT NULL constraints 
that is separate from CONSTRAINT_CHECK.