Hibernate ManyToOne vs OneToOne

Question

I can\'t see any difference in the schema of a Many-To-One relationship vs a OneToOne relationship:

@Entity
public class Order {

    @ManyToOne
    @JoinCol         


        

Answer 1

There should normally be a unique constraint on the address_id join column in the case of a OneToOne association, to guarantee that only one Order can have a given address.