Hibernate Criteria Return parent record that have one-to-one child record not null?

Question

I have a one-to-one relation like this

The Parent

@JsonAutoDetect
@Entity
@Table(name = \"Parent\")
public class Parent{

    private Integer id;
    p         


        

Answer 1

First of all, the mapping is wrong. In the parent class, you're saying that the association is mapped by child.parent, and immediately after you're saying that it's mapped using a join column named id_child. Make up your mind. Either it's mapped by the child.parent property, and you should remove the @JoinColumn. Or it's mapped by the JoinColumn and you should remove the @PrimaryKeyJoinColumn in the child, and use mappedBy="child" in the Child entity.

Now, to make your query work, whatever the mapping is, you should simply make an inner join:

Criteria criteria = session.createCriteria(Parent.class);
criteria.createAlias("child"); // inner join

Since the join is an inner join, it will only select parents that have a non-null child.