Question

Lets say I have two tables – “Cat” and “Cat owner” that are linked with many-to-one like this:

<class name="com.example.Cat" table="cat">
        ... 
        <many-to-one name="owner"
            class="com.example.CatOwner"
            column="owner_id" 
            not-null="false" insert="true" update="true" cascade="none" lazy="false"/>
</class>

Now I want to get a list of all cats sorted by cat owner names, like this:

session.createQuery("from Cat cat order by cat.owner.name");

The problem is if a cat doesn’t have an owner (owner_id=NULL), that cat won’t be selected with this query. How can I make cats without owners to be present in the result?

Thanks.

Answer 1

Take a look at Hibernate docs, 14.3. Associations and joins. Your query should be something like:

 from Cat cat left join cat.owner owner order by owner.name