[postgis-users] Adding constraint

[Mike Toews]

Add a check constraint with the logic:

ALTER TABLE test
  ADD CONSTRAINT aaa_atrib_2_not_null CHECK (
CASE
    WHEN attrib_1 = 'AAA'::text THEN attrib_2 IS NOT NULL
    ELSE true
END);

-Mike

On 26 April 2012 08:34, Piotr Pachół <piotrpachol at gmail.com> wrote:
> Hello,
> Is it possible to add constraint to second attribute of table only in the
> situation when first attribute of table equals specified value ?
> I give an example:
>
> CREATE TABLE test (
>    attrib_1 text,
>    attrib_2 text
> );
> INSERT INTO test VALUES ('AAA', 'QQQ');
> INSERT INTO test VALUES ('BBB', 'PPP');
>
>
> So is it possible to add  constraint (for instance NOT NULL) to attrib_2
> column if attrib_1 = 'AAA'
>
> Regards,
> Piotr
>
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