Re: Constants in the foreighn key constraints

On 11/22/19 11:36 PM, aleksey ksenzov wrote:

Please reply to list also.
Ccing list.

> We're already on 12.
> 
> While I understand I can do everything with triggers/functions, for me 
> it looks like a good idea to have possibility to use constants in 
> constraints, so it would be very nice if postgres community could add 
> this functionality in the nearest releases.
> Regards,
> Aliaksei.
> 
> 
> On Fri, Nov 22, 2019 at 4:25 PM Adrian Klaver <adrian.klaver@aklaver.com 
> <mailto:adrian.klaver@aklaver.com>> wrote:
> 
>     On 11/22/19 6:32 AM, aleksey ksenzov wrote:
>      > Hi team.
>      > Latest time we faced several issues which wouldn't arise provided we
>      > have possibility to use constants in foreign key constraints.
>      > brief example where it would be helpful:
>      >
>      > table_a
>      > ( id uuid,
>      > parent_id uuid,
>      > is_deleted boolean
>      > )
>      > having possibility of FK (parent_id, false) to (id, is_deleted)
>      > would disallow setting parent record deleted flag to true if they
>     have
>      > children, or insert record with is_deleted = true parent.
> 
>     Postgres version?
> 
>     Look at triggers, in particular CONSTRAINT triggers:
> 
>     https://www.postgresql.org/docs/12/sql-createtrigger.html
> 
>      >
>      > Regards,
>      > Aliaksei.
> 
> 
>     -- 
>     Adrian Klaver
>     adrian.klaver@aklaver.com <mailto:adrian.klaver@aklaver.com>
> 


-- 
Adrian Klaver
adrian.klaver@aklaver.com