JPA / Hibernate CreationTimestamp 不适用于 PrimaryKeyJoinColumn

Question

I am trying to use the @CreationTimestamp to automatically set the created date of the new entity, but it doesn't seem to be working from some reason.

ERROR: null value in column "created_at" violates not-null constraint

In the entity I have defined the annotation like this.

@CreationTimestamp
@Temporal(TemporalType.TIMESTAMP)
@Column(name = "CREATED_AT", nullable = false)
private Date createdAt;

Liquibase migration file:

<property name="date.type" value="TIMESTAMP WITH TIME ZONE" dbms="postgresql" />

<createTable tableName="USER">
    <column name="ID" type="${uuid_type}"><constraints nullable="false"/></column>
    <column name="CREATED_AT" type="${date.type}"><constraints nullable="false"/></column>
</createTable>

And the way I'm persisting the entity.

@Transactional(propagation = Propagation.REQUIRED)
public E insert(E e) {
    entityManager.persist(e);
    entityManager.flush();
    return e;
}

The code works when I set the createdAt date manually. But it does not generate one automatically what the annotation should do. Can anyone point me to why not?!

Answer 1

I had the same problem when I was looking for an answer here. This is how I annotated it to make it work:

@CreationTimestamp
@Column(name = "created", nullable = false, updatable = false)
@Temporal(TemporalType.TIMESTAMP)
private Date created;

I think the important part here is that the column is defined as not "updateable" - so the value will not be changed when updating the row. Because if it where "updateable" then JPA wouldn't generate the value.

However I had the "insertable=false" set as well which was wrong, because then JPA tried to persist it with a null value which throws an error because the column is set to be NOT NULL.