how to derefrence a field

sunh11373 · **Joined:** Thu May 05, 2005 11:54 pm **Posts:** 3

Hi,

How can map following relationship model:

Person [pid, name, department_id]
Department[did, department_name]

to object model:

Person[pid, name, department_name]

Thanks in advance.

jesse_sweetland · **Posted:** Fri May 06, 2005 3:04 pm

There are several approaches. First, you can use a formula column:

Code:

<hibernate-mapping>
   <class name="Person" table="Person">
      <id name="pid" column="pid">
          <generator class="native"/>
      </id>
      <property name="name" column="name"/>
      <property name="department_name" formula="select name from department where did=department_id"/>
    </class>
</hibernate-mapping>

That should work, depending on your database. Not to question your model, but it might be worthwhile to have a Person POJO with a many-to-one mapping to a Department POJO, and, if necessary, create a view like this:

Code:

create view PersonView as
select p.pid, p.name, d.name
from person p inner join department d
on p.department_id=d.did

You could then create a POJO and mapping called PersonView and use that as needed.

- Jesse[/code]

mveitas · **Posted:** Fri May 06, 2005 3:10 pm

Please follow directions and specify which version of hibernate you are using!!!!!!!!!!!

If you are using Hibernate3, then you might find this VERY useful :)
http://www.hibernate.org/hib_docs/v3/re ... ation-join