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@OneToOne(optional = false, ...) allows to save object with a null referenc

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I have a simple mapping: Category has a CategoryInfo reference. This is a one-to-one, not optional, and in one direction only. The database schema doesn't impose the not-null constraint on the foreign key.

<br />
@OneToOne(fetch = FetchType.EAGER, optional = false)<br />
@JoinColumn(name = "CATEGORY_INFO_ID")<br />
private CategoryInfo info;<br />

In the code, I create a new Category, and never assign a CategoryInfo to it, this is null, but the code runs fine, and the object is saved to the database. When I enable a not-null constraint, JDBC reports an error.

When I switch the provider from TopLink to Hibernate, and disable the not-null constraint again, running the same code results in an exception, which says that a not-null reference is null, which is what I expected.

So, there is a difference in behaviour between two providers. Could anyone tell me if this is allowed? Or maybe the optional attribute can be ignored by the provider?
I went here:
and this description lacks the "optional" attribute at all, hence my question if this is optional or not.

Thank you.

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Joined: 2005-07-06

For the optional tag, The JPA 1 Spec states:
"(Optional) Whether the value of the field or property may be null. This is a hint and is disregarded for primitive types; it may be used in schema generation."

It is optional (most hints are), but TopLink/EclipseLink will use the tag for schema generation - relying on the database to do validation if it is required. If you used schema generation for your tables, you'd see they were created with the not-null constraint.

Best Regards,