Horton

Re: cataloguing NOT NULL constraints

Alexander Lakhin <exclusion@gmail.com>

View thread
From: Alexander Lakhin <exclusion@gmail.com>
To: Alvaro Herrera <alvherre@alvh.no-ip.org>
Cc: Dean Rasheed <dean.a.rasheed@gmail.com>, Andrew Bille <andrewbille@gmail.com>, Peter Eisentraut <peter@eisentraut.org>, Robert Haas <robertmhaas@gmail.com>, pgsql-hackers@lists.postgresql.org
Date: 2024-05-03T04:00:00Z
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

02.05.2024 19:21, Alvaro Herrera wrote:

> Now, you could claim that the standard doesn't mention
> INCLUDING/EXCLUDING CONSTRAINTS, therefore since we have come up with
> its definition then we should make it affect not-null constraints.
> However, there's also this note:
>
>    NOTE 520 — <column constraint>s, except for NOT NULL, are not included in
>    CDi; <column constraint definition>s are effectively transformed to <table
>    constraint definition>s and are thereby also excluded.
>
> which is explicitly saying that not-null constraints are treated
> differently; in essence, with INCLUDING CONSTRAINTS we choose to affect
> the constraints that the standard says to ignore.

Thank you for very detailed and convincing explanation!

Now I see what the last sentence here (from [1]) means:
INCLUDING CONSTRAINTS

     CHECK constraints will be copied. No distinction is made between
     column constraints and table constraints. _Not-null constraints are
     always copied to the new table._

(I hadn't paid enough attention to it, because this exact paragraph is
also presented in previous versions...)

[1] https://www.postgresql.org/docs/devel/sql-createtable.html

Best regards,
Alexander