Java – JPA does not generate “on delete set null” FK restrictions

I have two related terms JPA notes Alarms and status An alarm can have a state

What I need is to be able to delete a state and "propagate" a null value to an alert in the deleted state

That is, I need to define the foreign key as "on delete set null"

@Entity
public class Alarm {
    @Id
    @GeneratedValue(strategy=GenerationType.SEQUENCE,generator="sequence")
    @SequenceGenerator(name="sequence",sequenceName="alarm_pk_seq")
    private Integer id;

    @OneToOne(cascade=CascadeType.ALL)
    @JoinColumn(name="idStatus")
    private Status status;

    // get/set
}

@Entity
public class Status {
    @Id
    @Column(name="idStatus")
    private Integer id;

    private String description;

    // get/set
}

Example:

Before:

STATUS
id  description
1   new
2   assigned
3   closed

ALARMS
id  status
1   1
2   2
3   2

After (delete status with id = 2)

STATUS
id  description
1   new
3   closed

ALARMS
id  status
1   1
2   NULL
3   NULL

I use hibernate and PostgreSQL to automatically generate databases from source code I tried every possible cascadetype and failed

Is there anything wrong with the code? Is it possible to use JPA?

Solution

Just add a comment using Hibernate:

@OnDelete(action=OnDeleteAction.CASCADE)

The generated foreign key is "on update no action on delete cascade"; “

But no action = ondeleteaction SET_ NULL

In addition, I don't like binding code to hibernate if possible (but I can use it if it works)

This thread discusses it I can't believe there is no simple way to generate foreign keys in JPA (or hibernate extension)