Hello,

I a fan of programatic query as most of the time
I have to generate a query from data given by the user
in a form. But I see some problems in the current Criteria API:

* It does not implement all the functionallity of hql.

* A criteria is associated with a session, so it is not possible
to store it for later retrieval (you could disconnect the session,
but ..).

Both of these problems are related to the fact that the criteria
api generates sql and executes this sql. Jus the same thing that
the session does. My concern is, would not be more logical that
the Criteria API would generate hql directly?

I mean something like:

Criteria criteria = new Criteria(Cat.class).add() ...
String hqlQuery = criteria.toHql();
session.find(hqlQuery);

This approach would have the following advantages:
* The Criteria API would generate hql instead of SQL. I understand
this is very desirable as avoid code duplication (currently
you have to generate sql from the hql code and from Criteria).

* The Criteria object is not related to any session, so you can
store, modify, reuse it ...

* You can modify the generated hql if needed to implement
things that the Criteria API does not provide.

What do you think about this? I am missiing something?

Regards.

It is not possible to recreate the same functionality the Criteria API currently has by using HQL. None of these two is a subset of the other.

There is a JIRA entry for detatched Criterias, you can vote for it here if it is important for you. But currently it does not look like it will get in in close future.

And don't you think it would be more sensible to extends hql
in order to support all the functionallity of the Criteria API and
unify all the code? In the best case, it can be confusing to have to
use one method or the other in order to access to some functionallity. In the worst, you have to maintain two separate
pieces; that leads to more work and more bugs.

To be able to detach the Criteria is one of the advantages
of the "unification", but is not one of my top needs by now :)

The HQL parser is being rewritten for the next major Hibernate release (no schedule yet), so we might see some unification of the two APIs.