Hi all !
I'm trying to fetch records from a JBPM application (which uses hibernate to map classes). The join I need to do is



It's a simple join between the ID of TaskInstance and ProcessInstance.

However The query delivers an error:
10:48:12,640 ERROR [STDERR] org.hibernate.hql.ast.QuerySyntaxException: org.jbpm.taskmgmt.exe.ProcessInstance is not mapped [from org.jbpm.taskmgmt.exe.TaskInstance t, org.jbpm.taskmgmt.exe.ProcessInstance p where t.id = p.id order by p.id
desc]

What's wrong with the query ?

Ehm sorry to raise another issue about it, but what kind of Object will this Query return ? Without the join



I get a List of TaskInstance objects, but with a join what kind of Object will be created in the List ? TaskInstance or ProcessInstance ? both ?

Thanks a lot for your help
Francesco

> What's wrong with the query ?

It might be some problems in how did you map org.jbpm.taskmgmt.exe.ProcessInstance. It is not a problem of the query. But the query look really strange. It is joined by primary id's of both classes, you know it is quite unusual and might be a bug. Anyway in a hibernate it is better to join by using mapping properties. Something like this:




> but what kind of Object will this Query return ?

Upd.

This is wrong:
-- It will return objects of instance TaskInstance in both cases. ---

This is a quote from the book:

"A Cartesian product allows you to retrieve all possible combinations of instances of two or more classes. This query returns all ordered pairs of Users and Category objects:

Obviously, this generally isn’t useful. There is one case where it’s commonly used: theta-style joins."

So I suppose it will return List of Object[] where element at index 0 will be of the class TaskInstance and element at index 1 will be of the class ProcessInstance

thanks for your reply.
I'm, sorry I made a silly mistake: ProcessInstance doesn't belong to org.jbpm.taskmgmt.exe package but to org.jbpm.graph.exe.
Correcting the package it works
Thanks
francesco