Spring Framework + Spring Data + Hibernate Jpa OneToMany child removal fails

Question

I have an unidirectional OneToMany JPA entity mapping in my (Spring Framework + Spring Data + Hibernate JPA) project. Entity classes are like in the following code.(I have removed irrelevant class members for brevity).

@Entity
@Table(name = "employees")
class Employee{
   @Id
   @GeneratedValue(strategy = GenerationType.IDENTITY)
   @Column(name = "id")
   private Integer id;

   @OneToMany(cascade = CascadeType.ALL, orphanRemoval = true)
   @JoinColumn(name = "employee_id")
   private List<DepartmentAssignment> departmentAssignments = new ArrayList<>();
}

@Entity
@Table(name = "department_assignments")
class DepartmentAssignment{
   @Id
   @GeneratedValue(strategy = GenerationType.IDENTITY)
   @Column(name = "id")
   private Integer id;

   @NotNull
   @Column(name = "employee_id")
   private Integer employeeId;

   @NotNull
   @Column(name = "department_id")
   private Integer departmentId;
}

@Entity
@Table(name = "departments")
class Department{
   @Id
   @GeneratedValue(strategy = GenerationType.IDENTITY)
   @Column(name = "id")
   private Integer id;       
}

And, in one of my service classes have a method to remove a DepartmentAssignment from an Employee like below.

public Employee deleteDepartmentAssignment(Integer empId, Integer deptAssignmentId) {
        Employee employee = employeeRepository.findOne(empId);
        if(employee != null) {
            for ( DepartmentAssignment da : employee.getDepartmentAssignments()) {
                if(da.getId().equals(deptAssignmentId)) {
                    employee.getDepartmentAssignments().remove(da);
                    employee = employeeRepository.save(employee);
                    break;
                }
            }
        }

        return employee;
    }

However, calling above methods gives me an error: org.hibernate.exception.ConstraintViolationException ,and in the SQL log, I can see Column 'employee_id' cannot be null error for the last SQL statement of the transaction.

Can anybody tell me what I'm doing wrong here and how to get it fixed?

Is there anything else in the DepartmentAssignment class? If not whats the point of it. You could remove it without any functional loss. — mh-dev, Mar 04 '16 at 10:48

score 1 · Accepted Answer · answered Mar 04 '16 at 09:11

1

You don't need to add

@NotNull
@Column(name = "employee_id")
private Integer employeeId;

to the Employee, if you use @JoinColumn(name = "employee_id"). Try to remove it.

answered Mar 04 '16 at 09:11

v.ladynev

19,275
8
46
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Trying your suggestion gives me the following error and it fails to load the spring context too. ` org.hibernate.DuplicateMappingException: Table [departments_assignments] contains physical column name [employee_id] represented by different logical column names: [employeeId], [employee_id] ` – Johna Mar 04 '16 at 09:22
@Tharanga You should remove all `employeeId` and `employee_id` from `DepartmentAssignment` and update a schema. – v.ladynev Mar 04 '16 at 09:27
I want to thank you. Removing employeeId altogether worked like a charm. – Johna Mar 04 '16 at 13:35
1

@Tharanga You are welcome. Thanks for up vote. `private Integer departmentId;` looks strange too. Please, never use such associations. You should to use associations to objects (using lazy, for an example). – v.ladynev Mar 04 '16 at 13:38

score 1 · Answer 2 · edited May 23 '17 at 12:08

You can try the following, not sure why you use the plain id in the object. Thats not object relational mapping. For more details see Hibernate triggering constraint violations using orphanRemoval

@Entity
@Table(name = "employees")
class Employee{
   @Id
   @GeneratedValue(strategy = GenerationType.IDENTITY)
   private Integer id;

   @OneToMany(cascade = CascadeType.ALL, mappedBy = "employee", orphanRemoval = true)
   private List<DepartmentAssignment> departmentAssignments = new ArrayList<>();
}

@Entity
@Table(name = "department_assignments")
class DepartmentAssignment{
   @Id
   @GeneratedValue(strategy = GenerationType.IDENTITY)
   private Integer id;

   @ManyToOne(optional=false)
   private Employee employee;

   @ManyToOne(optional=false)
   private Department department;
}

@Entity
@Table(name = "departments")
class Department{
   @Id
   @GeneratedValue(strategy = GenerationType.IDENTITY)
   private Integer id;       
}

Thank you for coming to help me. The reason I didn't make it bidirectional is that, according to my business model, it is not intended to access Employee from DepartmentAssignment. Your suggestion to make it bidirectional should work. I removed employeeId altogether from DepartmentAssignment entity, and it works as intended now. — Johna, Mar 04 '16 at 13:46

score 0 · Answer 3 · answered Mar 04 '16 at 09:11

0

You must look .hbm.xml file and you should mapping your Entity in this file and you can look this example

http://www.mkyong.com/hibernate/hibernate-one-to-many-relationship-example/

I hope it will be useful for you.

answered Mar 04 '16 at 09:11

java.nazif

713
1
9
18

It is not useful. Because of he uses mapping by annotations, not xm-mapping. – v.ladynev Mar 04 '16 at 09:12
I'm not using a .hbm file. Its all annotation based mapping with hibernate-jpa. – Johna Mar 04 '16 at 09:15

score -1 · Answer 4 · answered Mar 04 '16 at 09:19

-1

try removing

cascade = CascadeType.ALL

but im not 100% sure..

answered Mar 04 '16 at 09:19

Keaz

955
1
11
21

did u try it? , i this it is the reason – Keaz Mar 04 '16 at 09:45
It is impossible to update children via a parent with default `cascading`. – v.ladynev Mar 04 '16 at 09:50
Then add relevant cascade types not All. Like CascadeType.Merge – Keaz Mar 04 '16 at 09:54
It is possible. But, I think, the reason of an issue is not `cascade`. – v.ladynev Mar 04 '16 at 09:56
Hmm ok but CascadeType.All means that any change to the parent object will mark the child objects for update – Keaz Mar 04 '16 at 09:58

Spring Framework + Spring Data + Hibernate Jpa OneToMany child removal fails

4 Answers4