I am working on an application related to Bird Breeding records. Each year an exhibitor must purchase rings which are fitted to each bird for identification. I cannot set the RingNo field in the Table to indexed and no duplicates because there is a possibility (very slim) that one could over be issued with the same number/s in a different year. Can a primary key be set to have a combination of two fields (in this case RingNo and Year) where no duplicates would occur. If so could some explanation be given as to how this would be created. Thanks.