Обсуждение: Re: On insert duplicate row, return existing key

Anyone? Please

On Jul 31, 12:36 pm, Nick <nboutel...@gmail.com> wrote:
> If I insert a duplicate row into a table, id like to return the
> existing key.
>
> I tried creating a rule for this...
>
> CREATE RULE no_duplicates AS ON INSERT TO names WHERE EXISTS (SELECT 1
> FROM names WHERE new.name = name) DO INSTEAD SELECT id, name FROM
> names WHERE name = new.name;
>
> However, I get an error on...
>
> INSERT INTO names (name) VALUES ('existing') RETURNING *;
>
> ERROR:  cannot perform INSERT RETURNING on relation "names"
> HINT:  You need an unconditional ON INSERT DO INSTEAD rule with a
> RETURNING clause.

On 05/08/10 06:03, Nick wrote:
> Anyone? Please

It's probably going to be a lot easier to do this with a stored
procedure. I don't rate your chances of making it work with a rule.
Rules work more like a macro system, and I'm not sure they can be
convinced to do what you're trying to do.

--
Craig Ringer