| From: | Peter Eisentraut <peter(at)eisentraut(dot)org> |
|---|---|
| To: | Alvaro Herrera <alvherre(at)alvh(dot)no-ip(dot)org> |
| Cc: | pgsql-hackers <pgsql-hackers(at)postgresql(dot)org> |
| Subject: | Re: Catalog domain not-null constraints |
| Date: | 2023-11-27 07:08:08 |
| Message-ID: | 99adc944-bcc1-41bb-ae59-a10fb345f5dc@eisentraut.org |
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| Thread: | |
| Lists: | pgsql-hackers |
On 23.11.23 17:38, Alvaro Herrera wrote:
> If you create a table with column of domain that has a NOT NULL
> constraint, what happens? I mean, is the table column marked
> attnotnull, and how does it behave?
No, the domain does not affect the catalog entry for the column. This
is the same way it behaves now.
> Is there a separate pg_constraint
> row for the constraint in the table? What happens if you do
> ALTER TABLE ... DROP NOT NULL for that column?
Those are separate. After dropping the NOT NULL for a column, null
values for the column could still be rejected by a domain. (This is the
same way CHECK constraints work.)
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