Foreign key must have same number of columns as the referenced primary key for manyToMany - spring

Question

here job has a set of employees, and employee have a set of jobs, but Spring give me this exception
Caused by: org.hibernate.MappingException: Foreign key
(FK1kec5bwba2rl0j8garlarwe3d:account [employee_id])) must have same
number of columns as the referenced primary key (employee
[job_id,employee_id])
this is my employee class :
#Entity
public class Employee {
#Id
#GeneratedValue(strategy = GenerationType.AUTO)
private Integer id ;
private String firstname ;
private String lastname ;
private String email ;
private String phone ;
private String address ;
#OneToOne(cascade = CascadeType.ALL)
#JoinColumn(name = "account_id")
private Account account ;
public Account getAccount() {
return account;
}
public void setAccount(Account account) {
this.account = account;
}
#ManyToOne
#JoinColumn(name = "departement_id")
#JsonIgnore
private Departement departement ;
#ManyToMany(cascade = CascadeType.ALL)
#JoinTable(name = "jobs", joinColumns = #JoinColumn(name = "employee_id", referencedColumnName = "id"), inverseJoinColumns = #JoinColumn(name = "job_id", referencedColumnName = "id"))
private Set<Job>jobs ;
....
}
and here is my job class :
#Entity
#Inheritance
public abstract class Job {
#Id
#GeneratedValue(strategy = GenerationType.AUTO)
private Integer id ;
private String status ; // (pending or done)
private Date date ;
#ManyToMany(cascade = CascadeType.ALL)
#JoinTable(name = "employee", joinColumns = #JoinColumn(name = "job_id", referencedColumnName = "id"), inverseJoinColumns = #JoinColumn(name = "employee_id", referencedColumnName = "id"))
private Set<Employee> employee ;
#ManyToOne
#JoinColumn(name = "BusinnesPartner_id")
#JsonIgnore
private BusineesPartner busineesPartner ;
}
Please can you explain to me why I get this exception.

Answer 1

#JoinTable annotation should be used in the owning entity side , in the other side you should not have #JoinTable , you need to have mappedBy to define the reverse relation since you are establishing a bidirectional relation is if the Job is the owning entity you need to modify Employee pojo
#ManyToMany(cascade = CascadeType.ALL, mappedBy="employee")
private Set<Job>jobs ;