Re: Can arrays reference primary keys in CREATE TABLE?

From: Richard Huxton <dev(at)archonet(dot)com>
To: "Filipe Bonjour" <fbonjour(at)urbanet(dot)ch>, pgsql-sql(at)postgresql(dot)org
Subject: Re: Can arrays reference primary keys in CREATE TABLE?
Date: 2003-05-14 15:31:48
Message-ID: 200305141631.48642.dev@archonet.com
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On Friday 09 May 2003 10:21 pm, Filipe Bonjour wrote:
> Hi,
>
> I'm a rather new SQL user, and I found interesting that you can
> use "references" to make sure that a value inserted in a table is a
> primary key from another table. Something like:

Yep - referential integrity is vital.

> However, I'd like to define a table containing an array, and that
> all elements of the array be a primary key from another table, so I
> tried:
>
> create table tb (
> a_ref integer[] references ta(a_id)
> );
>
> But that doesn't work, I think because an array of integers can't
> be directly compared to an integer.

Don't use arrays, use another table, e.g.

CREATE TABLE tb_items (
tb_ref integer REFERENCE tb,
ta_ref integer REFERENCES ta,
PRIMARY KEY (tb_ref,ta_ref)
);

--
Richard Huxton

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