Обсуждение: Primary Keys

How can you create a Primary Key which contains multiple columns on for a
table.

I'll quote Thomas F.O'Connell on this one as it has been discussed just
some days ago:

<quote>
first of all, i recommend checking out the syntax for the CREATE TABLE
command. it's available here:

http://postgresql.readysetnet.com/users-lounge/docs/7.1/postgres/sql-cre
atetable.html

for a quick example, though:

create table foo (
    bar int4,
    baz int4,
    ola int4,
    primary key( bar, baz )
);

this statement will make the columns bar and baz coincidentally the
primary key for the table foo.

-tfo
</quote>

> -----Original Message-----
> From: pgsql-admin-owner@postgresql.org
> [mailto:pgsql-admin-owner@postgresql.org] On Behalf Of Brian Z
> Sent: Monday, April 30, 2001 11:21 PM
> To: pgsql-admin@postgresql.org.pgsql-general@postgresql.org
> Subject: [ADMIN] Primary Keys
>
>
> How can you create a Primary Key which contains multiple
> columns on for a table.
>
>
>
>
> ---------------------------(end of
> broadcast)---------------------------
> TIP 3: if posting/reading through Usenet, please send an
> appropriate subscribe-nomail command to
> majordomo@postgresql.org so that your message can get through
> to the mailing list cleanly
>

On Mon, 30 Apr 2001, Brian Z wrote:
> How can you create a Primary Key which contains multiple columns on for a
> table.
>
CREATE TABLE foo (
    col1    integer,
    col2    text,
    col3    timestamp,
    PRIMARY KEY (col1,col2)
);

Creates the primary key on columns col1 and col2. Please see the
documentation for CREATE TABLE for further information.

- Einar Karttunen