Question

I Am using hibernate and i have a Entity like

@Entity
@Table(name = "MyEntity")
Class MyEntity {
        @Id
    @GeneratedValue
    private long id;

    @Column(name = "NAME")
    private String name;

    //some more attributes here 

        @OneToOne
    @JoinColumn(name = "PARENT_ID")
        MyEntity parent;

}

I have one record in database

id   |  name | parent_id 

125 |   n1  |   null

and when i am trying to get this record with hibernate Query

Select e.id,e.name,e.parent.name from MyEntity e where e.id =125

this query is returning me zero records.because the parent is null here, so is there any way to handle this kind of situation.
thanks in advc.

Answer 1

In your case Hibernate implicitly uses inner join that doesn’t return anything when one of the sides is null.

You can instruct Hibernate to use left outer join instead as follows:

select e.id, e.name, p.name from MyEntity e left join e.parent p where e.id = 125