Обсуждение: Primary key

Hello,

Does postgres allow compound or composite keys for primary keys?  I
thought I read someplace that it didn't.  Now, I can't find a
reference to it.

Carol

--- Carol Walter <walterc@indiana.edu> wrote:

> Does postgres allow compound or composite keys for primary keys?  I
> thought I read someplace that it didn't.  Now, I can't find a
> reference to it.

It does.  composite key are defined as a table constraint:
http://www.postgresql.org/docs/8.2/interactive/sql-createtable.html

This link illistrates syntax with this example:

CREATE TABLE films (
    code        char(5),
    title       varchar(40),
    did         integer,
    date_prod   date,
    kind        varchar(10),
    len         interval hour to minute,
    CONSTRAINT code_title PRIMARY KEY(code,title)
);

Regards,
Richard Broersma Jr.

On 19 sep 2007, at 16.37, Carol Walter wrote:
> Does postgres allow compound or composite keys for primary keys?  I
> thought I read someplace that it didn't.  Now, I can't find a
> reference to it.

Yes, it does.

http://www.postgresql.org/docs/8.2/interactive/ddl-
constraints.html#AEN2080


Sincerely,

Niklas Johansson

Yes, PG allows  compound or composite keys for primary keys.

Igor

-----Original Message-----
From: pgsql-admin-owner@postgresql.org
[mailto:pgsql-admin-owner@postgresql.org] On Behalf Of Carol Walter
Sent: Wednesday, September 19, 2007 10:37 AM
To: pgsql-admin@postgresql.org
Subject: [ADMIN] Primary key

Hello,

Does postgres allow compound or composite keys for primary keys?  I
thought I read someplace that it didn't.  Now, I can't find a reference
to it.

Carol

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