Hibernate version:
3.0.3
Mapping documents:
n/a
Code between sessionFactory.openSession() and session.close():
n/a
Full stack trace of any exception that occurs:
n/a
Name and version of the database you are using:
MySql
The generated SQL (show_sql=true):
n/a
Debug level Hibernate log excerpt:
n/a

Question:
Ciao,

I have a persistent class Group that has lots of properties.
I would like to quiery my db for all Groups that match a certain Example instance of Group:

Group example = new Group();
example.setA("red");
example.setB("large");
example.setC(null);

List result = session.createCriteria(Group.class).add(Example.create(example).list();

As Null Values are excluded by default from the Criterias my Group.C Criteria is not regarded. In fact I wanted to explicitely search for Null Values in Property C.
The excludeNone() function I found not helpful here because that would mean that ALL null-valued properties of Group were regarded, not only C.

Is there any solution for respecting selected null values explicitely in an Example Query?

PS:
I have found a solution by using a CriteriaQuery:
if (null == group.getC()) {
crit.add(Expression.isNull("c"));
} else {
crit.add(Expression.eq("c", group.getC()));
}
..but I would prefer Example Queries..


Thanks
Kai

So, I guess one cannot use an Example Query here?!

It would be nice if there were a way to include() a single null property but it doesn't appear that there is. So you need to .excludeNone() and to turn off the null-exclusion and then exclude any additional properties you want to exclude from the example.

Thanks. I agree that it would be nice to include a single null value because in my case there are quite some properties to exclude....