Re: cataloguing NOT NULL constraints

Alvaro Herrera <alvherre@alvh.no-ip.org>

From: Alvaro Herrera <alvherre@alvh.no-ip.org>
To: Amit Langote <amitlangote09@gmail.com>
Cc: Laurenz Albe <laurenz.albe@cybertec.at>, Pg Hackers <pgsql-hackers@lists.postgresql.org>
Date: 2022-08-23T16:49:26Z
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 2022-Aug-22, Amit Langote wrote:

> Yeah, I think it makes sense to think of the NOT NULL constraints on
> their own in this case, without worrying about the PK constraint that
> created them in the first place.

Cool, that's enough votes that I'm comfortable implementing things that
way.

> BTW, maybe you are aware, but the legacy inheritance implementation is
> not very consistent about wanting to maintain the same NULLness for a
> given column in all members of the inheritance tree.  For example, it
> allows one to alter the NULLness of an inherited column:

Right ... I think what gives this patch most of its complexity is the
number of odd, inconsistent cases that have to preserve historical
behavior.  Luckily I think this particular behavior is easy to
implement.

> IIRC, I had tried to propose implementing the same behavior for legacy
> inheritance back in the day, but maybe we left it alone for not
> breaking compatibility.

Yeah, that wouldn't be surprising.

-- 
Álvaro Herrera         PostgreSQL Developer  —  https://www.EnterpriseDB.com/
"The problem with the facetime model is not just that it's demoralizing, but
that the people pretending to work interrupt the ones actually working."
                                                           (Paul Graham)