java - org.hibernate.MappingException: Repeated column in mapping for entity -

i have 2 domain-models: "userbean" , "loginbean". it's one-to-many relationship, user has many record of login. loginbean.userid foreign key of userbean.id . here ddl of database:

create table `users` (   `id` int(11) not null,   `username` varchar(255) default null,   `password` varchar(255) default null,   `register_date` datetime default null,   primary key (`id`) ) 

create table `login` (   `id` int(11) not null,   `user_id` int(11) not null,   `login_date` datetime not null,   `login_result` char(1) not null,   primary key (`id`),   key `user_id` (`user_id`),   constraint `login_ibfk_1` foreign key (`user_id`) references `users` (`id`) ) 

          @entity     @table(name = "login")     public class loginbean {         @id         @column(name = "id", nullable = false)         @genericgenerator(name = "ddd", strategy = "increment")         @generatedvalue(generator = "ddd")         private integer id; //pk          // fk --> user.id         @column(name = "user_id", nullable = false)         private integer userid;          @column(name = "login_date", nullable = false)         private date logindate;          @column(name = "login_result", nullable = false)         private boolean loginresult;          @manytoone         @elementcollection(targetclass = fordream.hibernate.bean.userbean.class)         private userbean user;          public integer getid() {             return id;         }          public void setid(integer id) {             this.id = id;         }          public integer getuserid() {             return userid;         }          public void setuserid(integer userid) {             this.userid = userid;         }          public date getlogindate() {             return logindate;         }          public void setlogindate(date logindate) {             this.logindate = logindate;         }          public boolean getloginresult() {             return loginresult;         }          public void setloginresult(boolean loginresult) {             this.loginresult = loginresult;         }          public userbean getuser() {             return user;         }          public void setuser(userbean user) {             this.user = user;         }     }  

and:

      @entity     @table(name = "users")     public class userbean {         @id         @genericgenerator(name = "abc", strategy = "increment")         @generatedvalue(generator = "abc")         private integer id; //pk          @column(name = "username")         private string username;          @column(name = "password")         private string password;          @column(name = "register_date")         private date register_date;          @onetomany(mappedby = "user", cascade = { cascadetype.merge })         private set loginset;          public set getloginset() {             return loginset;         }          public void setloginset(set loginset) {             this.loginset = loginset;         }          public integer getid() {             return id;         }          public void setid(integer id) {             this.id = id;         }          public string getusername() {             return username;         }          public void setusername(string username) {             this.username = username;         }          public string getpassword() {             return password;         }          public void setpassword(string password) {             this.password = password;         }          public date getregister_date() {             return register_date;         }          public void setregister_date(date register_date) {             this.register_date = register_date;         }     }  

when run application, message :repeated column in mapping entity: loginbean column: user_id (should mapped insert="false" update="false") checked every place, never defined "user_id" twice in "loginbean". that's why? !

your mapping bidirectional association. userbean parent , loginbean child. have 2 mappings user_id table

 @column(name = "user_id", nullable = false)     private integer userid; 

and

@manytoone     @elementcollection(targetclass = fordream.hibernate.bean.userbean.class)     private userbean user; 

with userid , user.id trying map user_id. totally removing userid field think had tried.

the explanation: @manytoone tag says go , @ class marked manytoone association mappings. , when goes userbean, finds loginbean associated userbean "user" property of loginbean. hibernate try , map userbean's id loginbeans field marked fk(in db) user table.