Horton

Re: [BUG] parenting a PK constraint to a self-FK one (Was: Self FK oddity when attaching a partition)

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

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From: Alvaro Herrera <alvherre@alvh.no-ip.org>
To: Zhihong Yu <zyu@yugabyte.com>
Cc: Jehan-Guillaume de Rorthais <jgdr@dalibo.com>, pgsql-hackers <pgsql-hackers@postgresql.org>
Date: 2022-08-23T17:50:59Z
Lists: pgsql-hackers 
On 2022-Aug-23, Zhihong Yu wrote:

> A bigger question I have, even with the additional filtering, is what if
> there are multiple constraints ?
> How do we decide which unique / primary key constraint to return ?
> 
> Looks like there is no known SQL statements leading to such state, but
> should we consider such possibility ?

I don't think we care, but feel free to experiment and report any
problems.  You should be able to have multiple UNIQUE constraints on the
same column, for example.

-- 
Álvaro Herrera         PostgreSQL Developer  —  https://www.EnterpriseDB.com/
"Postgres is bloatware by design: it was built to house
 PhD theses." (Joey Hellerstein, SIGMOD annual conference 2002)

Commits

  1. Create FKs properly when attaching table as partition

  2. Fix self-referencing foreign keys with partitioned tables

  3. Fix GetForeignKey*Triggers for self-referential FKs

  4. Choose FK name correctly during partition attachment

  5. Update SQL features

  6. Restore the previous semantics of get_constraint_index().