Setting Many To One relation to null with HQL

Hibernate ORM
1

I’m trying to set up a test in Hibernate for setting a many to many relation to null to investigate a related bug I’m dealing with, and I want to rule out the HQL as the issue.

Here is my test model:

@Entity(name = "person")
public static class Person {
	@Id
	@Column(name = "person_id")
	private Long id;

	@ManyToOne(fetch = FetchType.LAZY)
	@JoinColumn(name = "team_id")
	private Team team;

	public Person() {
	}

	public Person(Long id) {
		this.id = id;
	}

	public Team getTeam() {
		return team;
	}

	public void setTeam(Team team) {
		this.team = team;
	}
}

@Entity(name = "team")
public static class Team {
	@Id
	private Long id;

	public Team() {}

	public Team(Long id) {
		this.id = id;
	}
}

And my test query goes as follows:

Team team = new Team( 1L );
session.persist( team );

Person person = new Person( 1L );
person.setTeam( team );
session.persist( person );

person = session.find( Person.class, 1L );
assertNotNull( person.getTeam() );
session.createMutationQuery( "update person p set p.team = null" ).executeUpdate();
session.flush();
person = session.find( Person.class, 1L );
assertNull( person.getTeam() );

But in the final assertion it fails since the team is still pointing to the referenced team rather than null. Is anyone able to take a quick look at this and point out if I’m making any mistakes in my code?

2

You have to clear the persistence context after running a mutation query, since Hibernate ORM has no way of knowing if the mutation query changed any of the entities that are currently in the persistence context. Also read the note in the specification that explains this further: Jakarta Persistence

3

Thank you so much for the help @beikov that fixed it, I had tried flushing before and clearing the context afterwards but not both! All fixed now, best wishes!