When I am trying to delete Role from the roles table with the help of Hibernate using its id it occurs an exception:
com.mysql.jdbc.exceptions.jdbc4.MySQLIntegrityConstraintViolationException: Cannot delete or update a parent row: a foreign key constraint fails (`ewp`.`permissions`, CONSTRAINT `FK_sq51ihfrapwdr98uufenhcocg` FOREIGN KEY (`role_id`) REFERENCES `roles` (`id`))
Class User
...
@NotNull
@ManyToMany(fetch = FetchType.EAGER, targetEntity = Role.class)
@JoinTable(name = "permissions",
joinColumns = {@JoinColumn(name = "user_id")},
inverseJoinColumns = {@JoinColumn(name = "role_id")})
private Set<Role> roles;
...
Class Role
...
@ManyToMany(fetch = FetchType.EAGER)
private List<User> users;
...
When I add to Role
@JoinTable(name = "permissions",
joinColumns = {@JoinColumn(name = "role_id")},
inverseJoinColumns = {@JoinColumn(name = "user_id")})
private List<User> users;
Roles deleted without exceptions. But I think that it can work without mapping in Role.
You either need to determine which side of the Many-To-Many owns the relationship or make sure that you alter both sides prior to removing the associated Role objects.
As mentioned in the comments, you can imply ownership by adding a mappedBy attribute to either side of the relationship. By adding mappedBy="roles" to the Role entity, this will tell the persistence provider that the relationship is managed by the User object's roles property and thus to manipulate the relationship using its join-table mapping.