Thread: PRIMARY KEY and UNIQUE

PRIMARY KEY and UNIQUE

From

Erwin Ambrosch

Date:

21 February 2002, 16:39:37

Hi,

I have a such a table.

CREATE TABLE int_article (
  name          VARCHAR(12) UNIQUE
  headline      TEXT,
  summary      TEXT,
  main            TEXT,
  footer           TEXT,
  PRIMARY KEY (name)
);

Is the UNIQUE constraint neccessary, because if have specified the column
name to be the primary key.

Thanks in advance
Erwin

Re: PRIMARY KEY and UNIQUE

From

Darren Ferguson

Date:

21 February 2002, 17:00:29

No the unique constraint is not necessary because a primary key by
definition should be able to be used to uniquly define a row tuple
whatever it is called

Darren Ferguson

On Thu, 14 Feb 2002, Erwin Ambrosch wrote:

> Hi,
>
> I have a such a table.
>
> CREATE TABLE int_article (
>   name          VARCHAR(12) UNIQUE
>   headline      TEXT,
>   summary      TEXT,
>   main            TEXT,
>   footer           TEXT,
>   PRIMARY KEY (name)
> );
>
> Is the UNIQUE constraint neccessary, because if have specified the column
> name to be the primary key.
>
> Thanks in advance
> Erwin
>
> ---------------------------(end of broadcast)---------------------------
> TIP 4: Don't 'kill -9' the postmaster
>