mysql - SQL - phpmyadmin - Foreign Key errno: 150 -

i seen many topics have same issue me no 1 had answer case.

i've made model , sql script software. issue have errno: 150 foreign key in phpmyadmin. checked, both keys have same type issue still here.

can me resolve issue please ? had :

#1005 - can't create table `candidathlon`.`#sql-21ac_3b`  (errno: 150"foreign key constraint incorrectly formed") 

with request :

alter table participer_a    add constraint fk_participer_a_dateevenement foreign key (dateevenement)    references evenement(dateevenement) 

this tables have problem :

create table evenement(     numevenement  int (11) auto_increment  not null ,     nomevenement  varchar (25) not null ,     dateevenement date not null ,     primary key (numevenement ,dateevenement ) ,     index (nomevenement) )engine=innodb;  create table candidat(     datenaissance     date not null ,     numtelport        varchar (25) not null ,     numtelfixe        varchar (25) not null ,     adresse           varchar (25) not null ,     trouverentreprise bool not null ,     inscritcfa        bool not null ,     numpersonne       int not null ,     numstatut         int not null ,     numville          int not null ,     dateapprenti      date ,     numinstit         int not null ,     primary key (numpersonne ) ,     index (trouverentreprise ,inscritcfa ) )engine=innodb;   create table participer_a(     participeevent     bool not null ,     commentaireevent   varchar (100) ,     souhaiteparticiper bool not null ,     numpersonne        int not null ,     numevenement       int not null ,     dateevenement      date not null ,     primary key (numpersonne ,numevenement ,dateevenement ) )engine=innodb;  alter table participer_a add constraint fk_participer_a_numpersonne foreign key (numpersonne) references personne(numpersonne); alter table participer_a add constraint fk_participer_a_numevenement foreign key (numevenement) references evenement(numevenement); alter table participer_a add constraint fk_participer_a_dateevenement foreign key (dateevenement) references evenement(dateevenement); 

what want do:

alter table participer_a     add constraint fk_participer_a_dateevenement         foreign key (dateevenement) references evenement(dateevenement) 

the keys available on table:

primary key (numevenement ,dateevenement ) , index (nomevenement) 

neither of these starts dateevenement, is needed mysql foreign key constraint. need:

index (dateevenement) 

i imagine want this:

create table evenement(     numevenement  int (11) auto_increment  not null ,     nomevenement  varchar (25) not null ,     dateevenement date not null ,     primary key (numevenement),     index (dateevenement) ,     unique (nomevenement) ); 

numevenement unique on every row. auto_increment primary key in table has such column. guessing name of event unique. date might well, @ minimum, need index on it.