Question

Let’s I have entity A and entity B. Entity A have @OneToOne relationship with B.
I want do next:
if I remove A then B must be removed also.
If I remove B then A isn’t removed.

In which entity I must set

@OneToOne(cascade = {CascadeType.MERGE, CascadeType.PERSIST, CascadeType.REFRESH})  

and in which side I must set

@OneToOne(cascade = {CascadeType.ALL})  

?

Answer 1

The cascade from A to B should be placed on the field referencing B in class A, the cascade from B to A should be placed on the field referencing A in class B.

public class A {
    @OneToOne(cascade = {CascadeType.ALL})
    B b;
}

Should be in class A, as you want every action to be cascaded to B.

public class B {
    @OneToOne(cascade = {CascadeType.MERGE, CascadeType.PERSIST, CascadeType.REFRESH})
    A a;
}

Should be in class B, as you only want certain actions cascaded to A