Re: Are foreign key's automatically set as indicies? - Mailing list pgsql-general

On Wed, 16 May 2007 06:09:15 +0200, camb <mvpaustralia@gmail.com> wrote:

> Hey all,
> I'm sorta new to PG and am just wondering, when I create a foreign key
> is it automatically set as an indexed column or do I need to also set
> that manually?

    Primary key creates unique index.
    Foreign keys do not create any indexes, it is up to you to decide if you
need indexes or not.

    Say :

CREATE TABLE items ( ... category_id REFERENCES categories( id ) )

    if you want cascaded deletes/updates to your items table to be fast, or
you need it for other reasons, create an index on category_id.