Hi Community,
I'm testing hibernate as an replacement for our current selfmade persistence OR-mechanismn. For now, most works great but the devil is in the details.

The (web-)applications we build depend heaviliy on existing components (user/security-management, forum etc.). These objects are packaged in a reusable application-independent jar-file (e.g. a standard User-POJO with its corresponding user.hbm-mapping, see mapping).

Here is my question:

Having this (definitly not editable) user-mapping-file in the jar we can only specify unidirectional associations between the user-object and concrete application objects. For example in an CMS-application a user can publish articles (User:Article = 1:N). An article is associated with an user via a many-to-one association. The User object doesn't know anything about the existence of article-objects.


Mapping documents:

User (sitting in external jar):
<class name="User" table="t_user">
<id name="ID" column="a_id" type="java.lang.Long"><generator
class="native" /></id>
<property name="Login" column="a_login" type="java.lang.String" length="255"/>
<property name="Pwd" column="a_pwd" type="java.lang.String" length="255"/></class>
</hibernate-mapping>

Article (application):
<class name="Article" table="t_article">
<id name="ID" column="a_id" type="java.lang.Long"><generator class="native"/></id>
<property name="Text" column="a_text" type="text"/>
<property name="Words" column="a_words" type="int"/>
<!-- association with user -->
<many-to-one name="Editor" class="User" column="a_userid" not-null="true"/>
</class>


Having this design, is it possible to query (criteria-api would be great, but hsql is no show stopper also) user objects for concrete features like the following one: Give me all users that have written articles containing e.g. more than words? Is this possible with one query/criteria or do we have to select all articles first and then loop over the result and collect the user?

Regards

Paul

Paul,
First of all: don't use capital startling letter for your attributes, it's bad desgin.
Answer to your question:
The following query probably works:


Please read the documentation. It's all explained there. See chapter 11 for the HQL features.

Greetz[/code]

Is it possible to use the Criteria API to make the same query?

Thanks,
zeng

The Criteria query api is limited. Aggregated functions are not supported(yet). Look at Chapter 12 for the currently supported options. Hope this helps.