i have a persistent object which has a set mapped to it. the mapping looks something like this:


<hibernate-mapping>
<class name="org.MyPeristentCollection" schema="MYSCHEMA" table="MyPersistentCollection">
<cache usage="read-write"/>
<id column="N_COLLECTION_ID" name="id" type="long">
<generator class="sequence">
<param name="sequence">MYSCHEMA.N_COLLECTION_ID_COUNTER</param>
</generator>
</id>

<set name="members" table="MYSCHEMA.COLLECTION_TO_MEMBER" lazy="true">
<cache usage="read-write"/>
<key column="N_COLLECTION_MEMBER_ID"/>
<many-to-many class="org.CollectionMember" column="N_COLLECTION_MEMBER_ID" />
</set>
</class>
</hibernate-mapping>

this works well. the problem i'm facing is i need a list of the sizes of these collections. something like:

select c.members.size from MyPersistentCollection c

but of course, size doesn't map to a mapped property. how can i fix this without loading the members set?

Try this:
<query name="test">
select size(c.members) from MyPersistentCollection c
</query>


then your hibernate code:

query = session.getQuery("test");

int x = Integer.parseInt(String.valueOf(query.list().get(0)));


i guess that will help you.

request for comments.

This might help:

using either count() or size() gives me the aggregate size of all members. what i would like is a list of the individual size of each member set.

Do you mean something like 'group by' MyPeristentCollection.id?

to clarify what i'm trying to get...
for example:
if i had 3 collections, each with 10 members.
when i query for the sizes, i'd like to retrieve a list of integers with the values 10,10,10.