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Re: Primary key not unique on InnoDB table

From: Tompkins Neil (neil.tompkinsgooglemail.com)
Date: Wed Oct 13 2010 - 09:51:10 CDT


Sorry Joao, I thought that was pretty standard to have a primary key with
auto_increment ??

2010/10/13 João Cândido de Souza Neto <joaoconsultorweb.cnt.br>

> Sorry, the word is counpound instead of composed.
>
> --
> João Cândido de Souza Neto
>
> ""João Cândido de Souza Neto"" <joaoconsultorweb.cnt.br> escreveu na
> mensagem news:20101013144314.9787.qmaillists.mysql.com...
> > I´d never seen before a composed primary key that has an auto_increment
> > field on it.
> >
> > May be I can be wrong but I think it wont work properly.
> >
> > As far as I know, if you have an auto_increment field it must be your
> > single primary key. Am I wrong?
> >
> > --
> > João Cândido de Souza Neto
> >
> > "Tompkins Neil" <neil.tompkinsgooglemail.com> escreveu na mensagem
> > news:AANLkTi=-1wVUxDFsQ4KM6RfZ0wsRLpPHuG1bnt4X9RhKmail.gmail.com...
> >> 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
> >>
> >
> >
>
>
>
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