I've the following table. But why isn't the primary key unique, e.g. preventing duplicates if entered ?
CREATE TABLE `players_master` ( `players_id` bigint(20) NOT NULL AUTO_INCREMENT, `default_teams_id` bigint(20) NOT NULL, `first_name` varchar(100) COLLATE utf8_unicode_ci NOT NULL, `second_name` varchar(100) COLLATE utf8_unicode_ci NOT NULL, `known_as` varchar(200) COLLATE utf8_unicode_ci DEFAULT NULL, `dob` date NOT NULL, `countries_id` char(2) COLLATE utf8_unicode_ci NOT NULL, `retirement_date` date DEFAULT NULL, `positions_id` varchar(3) COLLATE utf8_unicode_ci NOT NULL, `estimated_value` double NOT NULL DEFAULT '0', `contract_wage` double NOT NULL DEFAULT '0', `rating` int(11) NOT NULL, PRIMARY KEY (`players_id`,`default_teams_id`), KEY `FK_players_master_countries_id` (`countries_id`), KEY `FK_players_master_positions_id` (`positions_id`), KEY `IDX_first_name` (`first_name`), KEY `IDX_known_as` (`known_as`), KEY `IDX_second_name` (`second_name`), KEY `IDX_dob` (`dob`), KEY `IDX_estimated_value` (`estimated_value`), KEY `IDX_contract_wage` (`contract_wage`), KEY `IDX_rating` (`rating`), KEY `FK_players_master_teams_id` (`default_teams_id`), CONSTRAINT `FK_players_master_countries_id` FOREIGN KEY (`countries_id`) REFERENCES `countries` (`countries_id`) ON DELETE NO ACTION ON UPDATE NO ACTION, CONSTRAINT `FK_players_master_positions_id` FOREIGN KEY (`positions_id`) REFERENCES `positions` (`positions_id`) ON DELETE NO ACTION ON UPDATE NO ACTION, CONSTRAINT `FK_players_master_teams_id` FOREIGN KEY (`default_teams_id`) REFERENCES `teams_master` (`teams_id`) ON DELETE NO ACTION ON UPDATE NO ACTION ) ENGINE=InnoDB AUTO_INCREMENT=1001 DEFAULT CHARSET=utf8 COLLATE=utf8_unicode_ci I'm confused, I thought primary keys were always unique ? Cheers Neil