From: Tom Lane <tgl@sss.pgh.pa.us>
To: zheng_xianghang@163.com
cc: pgsql-bugs@lists.postgresql.org
Subject: Re: BUG #19444: conkey field empty for domain NOT NULL constraint in pg_constraint (18.3)
In-reply-to: <19444-21f73da373fc0f58@postgresql.org>
References: <19444-21f73da373fc0f58@postgresql.org>
Comments: In-reply-to PG Bug reporting form <noreply@postgresql.org>
	message dated "Mon, 30 Mar 2026 03:10:45 -0000"
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Date: Mon, 30 Mar 2026 14:44:18 -0400
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PG Bug reporting form <noreply@postgresql.org> writes:
> When creating a domain with a NOT NULL constraint, the conkey field in
> pg_constraint remains empty. This is inconsistent with table-level NOT
> NULL constraints, which correctly populate the conkey field.

I do not think this is a bug.  The system catalog documentation says

    conkey int2[] (references pg_attribute.attnum)

      If a table constraint (including foreign keys, but not
      constraint triggers), list of the constrained columns

So (a) this is not a table constraint, and (b) a domain does not have
columns.

			regards, tom lane