Hi,

I have an entity which has another entity associated as a oneToOne.
I want to return null for some specific values of the connecting column (e.g: when the column value is -1). how can I do that?


Many thanks, Uri.

Hey Uri,

Why not just allow nulls in the column?

I was trying to find an answer to your same question. Then I realized there was no real reason why I wanted to do it. I had always just kept nulls out of number columns because it means writing less code for data access. However, when using Hibernate, Hibernate handles all of that for you. In hibernate world having a null in a numeric column is no problem (as far as I can tell).

Hi sowelie,

Thank you for your reply. The problem is I am working with a legacy DB.
The column that serves as the join-column in my table is receiving normal values (id's for the refrenced table) and also get the -99 value which basically says there is a different type of relation.

The main problem is that this is a legacy DB and I must support the already existing features/behaviors.

My solution was to write an xml mapping, because JPA/hibernate annotations currently don't support formula the way xmls do.

I defined the problematic property as such:
<one-to-one name="problematicProperty" class="com.blabla.someEntity" access="field">
<formula>case when someEntity_id=-99 then null else someEntity_id end</formula>
</one-to-one>