discriminator. I want to ignore some values?

yagami · **Joined:** Fri Jan 05, 2007 5:36 am **Posts:** 16

I'm mapping from an old database right now.
There is some values that need to be there and can't be changed but I don't want them when I retrieve my objects.
Right now I have a discriminator that maps the objects right but here comes the problem.
I don't know how to leave some of the values out from the discriminator?

Let's say the column contains values from 1-17. I only want it to return values from 1-10 and 16-17.

I have tried some different solutions but none of them have worked so far.
How can this be done?

Cheers,

Yagami.

gonzao_diaz · **Joined:** Mon Nov 26, 2007 2:29 pm **Posts:** 443

yagami,

Two possible solutions:
1) create a view on your database and map to that, as if it were a normal table.
2) Make a "subselect" class (Chapter 5.1.3)

yagami · **Joined:** Fri Jan 05, 2007 5:36 am **Posts:** 16

Thanks a lot!

I created a view and now everything works like a charm.
My only question now is how NHibernate will handle insert and updates.

gonzao_diaz · **Joined:** Mon Nov 26, 2007 2:29 pm **Posts:** 443

Yagami,
What worked for me, is to have 2 versions of the entity: one "full" and one "abridged". The "abridged" is the one that has the view or subselect ad backend, and the "full" is the one that you would use when you need to update/insert/delete.

Notice that Hibernate does not like many objects floating around with the same ID, so, in order for this solution to work, you would have to make the "full" id a property of the "abridged" id, and indicate in the mapping file that "abridged" takes its ID from "full". This is indicated with the id generator called "foreign", in the following way:

Code:

<class name="abridgedClass">
  <id name="id" column="classId">
    <generator class="foreign">
      <param name="property">fullClass</param>
    </generator>
  </id>
  ...
  <one-to-one name="fullClass" class="FullClass" constrained="true"/>
  ...
</class>

<class name="fullClass" table="fullClass">
...

(reference documentation 5.1.1)