Re: Triggers in postgres

Foreign Keys should be able to do what you want.
Example, not at all tested:
CREATE TABLE product (    barcode serial,
                PRIMARY KEY (barcode));
CREATE TABLE catalog (    pk serial,
                fk int4,
                PRIMARY KEY (pk),
                FOREIGN KEY (fk) REFERENCES product
(barcode) ON DELETE CASCADE );

When an entery in the product table is deleted, any enteries in catalog with
fk=barcode should be deleted as well.
For more info see CREATE TABLE in the DOCs
(eg http://www.postgresql.org/idocs/index.php?sql-createtable.html )
Also you should be able to add foriegn keys using ALTER TABLE
Hope this helps,
- Stuart

> -----Original Message-----
> From: Rob [mailto:rob@obsidian.co.za]
> Sent: 19 March 2002 16:40
> To: pgsql-novice@postgresql.org
> Subject: [NOVICE] Triggers in postgres
>
>
> Hi,
>
> I have a product table with a column barcode.  After a
> product has been
> deleted, I want to create a trigger to delete references to
> that product
> in other tables.  I've got the following trigger
>
> CREATE TRIGGER
> AFTER DELETE
> ON TABLE product
> FOR EACH ROW
>
> Now, what I would ideally like to do is issue a simple sql
> delete command,
> but I think I actually have to define a function (is this
> true?).  Say I
> do, then the rest of my trigger would look like
>
> EXECUTE PROCEDURE someProc();
>
> Now I need to pass somProc the barcode of the product I've
> just deleted.
> How do I do this?
>
> Thanks
>
> Rob
>
> --
> He who dies with the most toys ...
>
>                     ... still dies
>
>
>
> ---------------------------(end of
> broadcast)---------------------------
> TIP 2: you can get off all lists at once with the unregister command
>     (send "unregister YourEmailAddressHere" to
> majordomo@postgresql.org)
>