| 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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| Lists: | pgsql-sql |
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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