Re: Rule Question

On Wed, Jul 24, 2013 at 11:44 PM, Andrew Bartley <ambartley(at)gmail(dot)com> wrote:
> Hope this question is not too stupid but......
>
> I am trying to do something like this
>
> create table cats (a text,b text);
>
> create rule cats_test as on update to cats do set a = new.b;
>
> Can i manipulate column "a" sort of like this... or is there a better way.
>
> I would like to do this as the construction of the new.b value is complex
> and time consuming, so I just want to do it once.
>
> update cats
> set b = something_complex_and_time_consuming(b);

AFAIK, the best way here is to use trigger that does new.a = new.b.

--
Kind regards,
Sergey Konoplev
PostgreSQL Consultant and DBA

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