I couldn't help but notice you have individual indexes on nearly all the
fields of your table. If you won't be using these fields exclusively as a
join or filter condition in a query, you are unlikely to benefit from the
extra indexes and, in fact, they could slow down your inserts and add to
your storage requirements.
-Travis
-----Original Message-----
From: Tompkins Neil [mailto:neil.tompkins@stripped]
Sent: Wednesday, October 13, 2010 8:37 AM
To: [MySQL]
Subject: Primary key not unique on InnoDB table
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
