Getting not-null errors despite having a default value set.

Question

I have the following database column:

 `last_modified` timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP

With the following mapping in hibernate:

@Temporal(TemporalType.TIMESTAMP)
@Column(name="last_modified", nullable=false, length=19)
public Date getLastModified() {
    return this.lastModified;
}

This has been working fine for months now but all of a sudden out of nowhere I am getting the following error:

javax.persistence.PersistenceException: org.hibernate.PropertyValueException: not-null property references a null or transient value: com.fs.model.BrowserHistory.lastModified

So I am wondering, why is this happening all of a sudden? Is it OK if I set the lastModified field to be nullable?

Answer 1

Looks like you would like to record the modification timestamp. To avoid setting it manually (or not setting it and getting errors) you can use lifecycle callbacks:

@PrePersist
public void updateTimestamps() {
    lastModified = new Date();
}

Answer 2

I found out that database generated columns need some specific annotations:

@Column(name="last_modified", nullable=false, length=19, insertable=false, updatable=false)
@Generated(GenerationTime.ALWAYS)

We are trying this out now but I think it will fix the issue.