How to write this query

Hi all Plz se this below

UsersID!!!!!!! name !!!!!!!Match_ID!!!!!!!!!!!! Matches

===================================

1!!!!!!!!!!!!USER1!!!!!!!!21 !!!!!!!!! IND vs S.A

2!!!!!!!!!!!!USER2!!!!!!!!301 !!!!!!!! AUS vs S.A

.:

..:

=======================================================

My Question is :

1>User1 must be able to bet matches for only one time ie (User1 can bet Match_ID 21 and 301 but only for one time )

2> similarly for User2

3> and so on

4> What i am doing is I am giving Primary key For the Match_ID so

for only User1 it is satisfying the condition but for User2 it is showing this error:-> java.sql.SQLException: Duplicate entry '301' for key 1

So how do we proceed plz give me hint

Thanks

Message was edited by:

saamer

[863 byte] By [saamera] at [2007-11-27 2:06:08]