mysql - SQL PRIMARY KEY duplicate error same PRIMARY KEY across 3 tables -

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getting error having duplicate primary key. how can use same primary key across multiple tables? showing how can use in tables below appreciated. error com.mysql.jdbc.exceptions.jdbc4.mysqlintegrityconstraintviolati onexception: duplicate entry 'jam' key 'primary'

    create table `skills` (       `playername` varchar(15) not null default '',       `testa` double default null,       `testb` double default null,       `testc` double default null,       `testd` double default null,       primary key  (`playername`)     ) engine=myisam;      create table `playerrights` (       `playername` varchar(15) not null default '',       `rank` int(2) default null,       primary key  (`playername`)     ) engine=myisam;      create table `skillsoverall` (       `playername` varchar(15) not null default '',       `lvl` int(11) default null,       `xp` bigint(11) default null,       primary key  (`playername`)     ) engine=myisam;

you can't spread primary key across multiple tables. should have table called players 1 row per player, , these 3 tables should have foreign key pointing that.

the playername column can indeed primary key on each of 3 tables want be, it's unlikely that's want. if want there more 1 row per player in of these tables, shouldn't pk on tables.

a primary key means 2 things:

  1. unique (no 2 rows can have same value column(s))
  2. not null

the error got reflects row you're inserting violate #1.

the foreign key players table ensures referential integrity. nothing stored players don't exist. , players stats stored aren't removed prior stats being removed, etc.

this first table's ddl fk players table (you should have such table):

create table `skills` (   `playername` varchar(15) not null default '',   `testa` double default null,   `testb` double default null,   `testc` double default null,   `testd` double default null,    index (playername),    constraint fk_playername_rights   foreign key (playername) references players (playername)     on delete restrict     on update restrict   ) engine=myisam;

note: can change restrict cascade if want effect (based on want have happen if attempt change or remove player in players table)


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