| From: | Stephane Bortzmeyer <bortzmeyer(at)nic(dot)fr> | 
|---|---|
| To: | Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> | 
| Cc: | Stephane Bortzmeyer <bortzmeyer(at)nic(dot)fr>, Scott Marlowe <smarlowe(at)g2switchworks(dot)com>, Guy Rouillier <guyr(at)masergy(dot)com>, pgsql-general(at)postgresql(dot)org | 
| Subject: | Re: PRIMARY KEY on a *group* of columns imply that each column is NOT | 
| Date: | 2005-04-27 14:36:49 | 
| Message-ID: | 20050427143649.GA848@nic.fr | 
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| Lists: | pgsql-general | 
On Wed, Apr 27, 2005 at 10:26:30AM -0400,
 Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote 
 a message of 9 lines which said:
> If that's what you want, declare it as UNIQUE not PRIMARY KEY.
As shown by Patrick TJ McPhee, it does not work:
tests=>  create table x (
tests(>    name TEXT NOT NULL,
tests(>    address INET,
tests(>    CONSTRAINT na UNIQUE (name, address)
tests(>  );
NOTICE:  CREATE TABLE / UNIQUE will create implicit index "na" for table "x"
CREATE TABLE
tests=> INSERT INTO x (name) values ('foobar');
INSERT 45380 1
tests=> INSERT INTO x (name) values ('foobar');
INSERT 45381 1
tests=> INSERT INTO x (name) values ('foobar');
INSERT 45382 1
tests=> INSERT INTO x (name) values ('foobar');
INSERT 45383 1
tests=> select * from x;
  name  | address 
--------+---------
 foobar | 
 foobar | 
 foobar | 
 foobar | 
(4 rows)
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