I would need to perform a criteria query on two unrelated tables (entities) that, if I was using HQL instead of the Criteria API, I would query using something like this:



It must be noted that that a_field and another_field are not primary/foreign keys of these tables. Additionally, since one of the tables is updated by an external application and has a fixed structure, I cannot add a foreign key to it.

That's why I cannot join the two entities using createCriteria() or createAlias(). On the other hand the Criteria API doesn't seem to support more than one root entity, so I cannot directly translate the above HQL query into a sequence of Criteria API calls. Nevertheless, I would like to be able to use the Criteria API instead of HQL because the <extra_conditions> mentioned in the HQL query above are variable, depending on user input.

Do I have any chance of using the Criteria API under these circumstances?

Thanks in advance.