如何通过Hibernate删除关联实体

Question

I've two classes and corresponding to them two tables. Please assume that all the getters and setters have been added to the classes.

public class Employee implements Serializable {

//@ManyToOne( cascade = CascadeType.PERSIST, targetEntity = RackEntity.class )
//@Fetch( FetchMode.SELECT )
//@JoinColumn( name = "orgName", referencedColumnName = "orgName", nullable = true )
//private Organization org;

private Long id;
private string empName;

@LazyCollection( LazyCollectionOption.FALSE )
@OneToMany( mappedBy = "emp", cascade = { CascadeType.ALL } )
@Cascade( { org.hibernate.annotations.CascadeType.SAVE_UPDATE, org.hibernate.annotations.CascadeType.DELETE,
        org.hibernate.annotations.CascadeType.MERGE, org.hibernate.annotations.CascadeType.PERSIST } )
private Set<Address> empAddress;
}

and

public class Address implements Serializable {

@ManyToOne( cascade = CascadeType.PERSIST, targetEntity = RackEntity.class )
@Fetch( FetchMode.SELECT )
@JoinColumn( name = "empName", referencedColumnName = "empName", nullable = true )
private Employee emp;

private Long id;
private String street;
private String block;

}

Now when I try to delete Employee entity, it successfully deletes it including the associated Address entities.

public void deleteById(Long id) {
    logger.info("Deleting Employee {}", id);
    Employee entity = (Employee) sessionFactory.getCurrentSession()
            .get(Employee.class, id);
    sessionFactory.getCurrentSession().delete(entity);
    sessionFactory.getCurrentSession().flush();
}

But problem comes when I uncomment the code in the Employee class after introducing another class, Organization along with corresponding table as follows:

public class Organization implements Serializable {

private Long id;
private string orgName;

@LazyCollection( LazyCollectionOption.FALSE )
@OneToMany( mappedBy = "org", cascade = { CascadeType.ALL } )
@Cascade( { org.hibernate.annotations.CascadeType.SAVE_UPDATE, org.hibernate.annotations.CascadeType.DELETE,
        org.hibernate.annotations.CascadeType.MERGE, org.hibernate.annotations.CascadeType.PERSIST } )
private Set<Employee> emps;
}

Here, after populating the DB appropriately, when I try to delete Employee entity using same method, I get the following exception:

org.hibernate.ObjectDeletedException: deleted object would be re-saved by cascade (remove deleted object from associations)

I guess this is because the Employee entities are still being referred in the Organization entity in the form of the field, emps. I tried to find out the solution but didn't get anything elaborate one though.

So could anyone help me in resolving this Exception error along with concrete justifications ??

Answer 1

My idea would be to try and add orphanRemoval = true (in the OneToMany -Line) to Organization and then just to delete the Employee out of the Set. It should remove the everything nicely.

A bit outdated: https://docs.oracle.com/cd/E19798-01/821-1841/giqxy/