Hi!...

Normally, there is only one attribute for the primary
key but in my table, my primary key is composed of two
attributes. How do I state this in SQL? What if
Region_num and Num_Players, combined, should form a
primary key?

CREATE TABLE REGION (
Region_Num smallint primary key,
Num_Players smallint,
Player_Num smallint
);

Thanks!

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On Sun, Dec 28, 2003 at 20:21:32 -0800,
Peggy Go <shatz_go (AT) yahoo (DOT) com> wrote:
Region_Num smallint,
Num_Players smallint,
Player_Num smallint,
primary key (Region_Num, Num_Players)
);

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On Sun, Dec 28, 2003 at 08:21:32PM -0800, Peggy Go wrote:
See the documentation for primary keys and for CREATE TABLE:

http://www.postgresql.org/docs/curre...s.html#AEN1972
http://www.postgresql.org/docs/curre...eatetable.html

--
Michael Fuhr
http://www.fuhr.org/~mfuhr/

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Bruno Wolff III (Sunday 28 December 2003 23:24)
You might also find unique () to be very helpful. I personally prefer to
always have an id column as the primary key in any table, and to further
constrain the table with unique's, where necessary.

create table foobar (
id bigint default nextval(foobar_seq),
foo varchar(32),
bar smallint,
foob text,
primary key (id),
unique (foo, bar)
);

Vertu sæll,

--
Sigþór Björn Jarðarson (Casey Allen Shobe)
http://rivyn.livejournal.com

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Bruno Wolff III (Monday 29 December 2003 12:14)
Oops! You're right, and the ID column needs a 'not null' as well. I just
typed that in a hurry and forgot. Sorry.

Vertu sæll,

--
Sigþór Björn Jarðarson (Casey Allen Shobe)
http://rivyn.livejournal.com

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On Mon, Dec 29, 2003 at 10:35:54 -0500,
Casey Allen Shobe <cshobe (AT) softhome (DOT) net> wrote:
Note that isn't quite the same unless you add NOT NULL constraints for
foo and bar.

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On Mon, Dec 29, 2003 at 12:09:01 -0500,
Casey Allen Shobe <cshobe (AT) softhome (DOT) net> wrote:
A primary key constraint implies both unique and not null, so you don't
need to use NOT NULL on the ID column.

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Bruno Wolff III (Monday 29 December 2003 12:21)
Man I'm really acting rusty today...sorry again :\

Vertu sæll,

--
Sigþór Björn Jarðarson (Casey Allen Shobe)
http://rivyn.livejournal.com

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