<array>, cascade="all-delete-orphan" and upd

chaessig · **Joined:** Tue Jan 16, 2007 5:42 am **Posts:** 4

Hi,

I've a problem when using an array with cascade="all-delete-orphan", during an update of my objects.

The use of <array>, instead of a <set> for example, is necessary due to external constraints.

I have 2 classes : WSPatient, which contains an array of WSStudy. So there is a one-to-many relation between WSPatient and WSStudy.

Both classes derive from WSAbstract.

NHibernate version : 1.0.3

Mapping files :

Code:

<hibernate-mapping xmlns="urn:nhibernate-mapping-2.0">
  <class name="MedicaWS.WSAbstract,App_Code.kokucnts" table="Abstract">

    <id name="ObjectID"  column="ObjectID" type="Int32" unsaved-value="0" >
      <generator class="native"/>
    </id>
  </class>
</hibernate-mapping>

Code:

<hibernate-mapping xmlns="urn:nhibernate-mapping-2.0">
   <joined-subclass name="MedicaWS.WSPatient, App_Code.kokucnts" 
                  extends="MedicaWS.WSParam,App_Code.kokucnts" 
                  table="Patient">

      <key column="ID"/> 
      <property name="Name" column="Name" type="String" length="50"/> 
...
    <array name="Studies" table="Study" cascade="all-delete-orphan" >
      <key column="Patient" />
      <index column="StudyIndex" />
      <one-to-many class="MedicaWS.WSStudy, App_Code.kokucnts" />
    </array>
  </joined-subclass>
</hibernate-mapping>

Code:

<hibernate-mapping xmlns="urn:nhibernate-mapping-2.0">
   <joined-subclass name="MedicaWS.WSStudy,App_Code.kokucnts" 
                  extends="MedicaWS.WSParam,App_Code.kokucnts" 
                  table="Study">

      <key column="ID"/>
    
      <property name="RisID" column= "RisID" type="String" length="50"/>  
...
    <many-to-one name="Patient" 
                 class="MedicaWS.WSAbstract,App_Code.kokucnts" 
                 column="Patient" />

  </joined-subclass>
</hibernate-mapping>

The problem :
In my database, I've one WSPatient, which has 2 WSStudy in its array.
Reading the objects works very well : I've my WSPatient instance, having 2 WSStudy instances in its Studies array.

But when I try to remove the second study, NHibernate only sets the Patient and StudyIndex fields to NULL, without removing the whole study. And this despite of cascade="all-delete-orphan"

The code is very simple. I build a session, a transaction, call session.Update () and commit the transaction.

Does anyone have information about the use of <array> and cascade="all-delete-orphan" ?
Or even better, a solution to my problem ? :)

Thanks in advance !

Christian

mnichols · **Joined:** Mon Aug 21, 2006 9:18 am **Posts:** 179

Could post the code you use to remove the child from the parent collection?
I haven't used the <array/> but it seems to me that you may not be removing the reference on both sides.

chaessig · **Joined:** Tue Jan 16, 2007 5:42 am **Posts:** 4

Thanks for reply,

sure, here's the code which removes a child :

Code:

        
wsPat.Studies[1] = null;   // remove the instance of the child
WSStudy[] arStudies = wsPat.Studies;  // resize the array
Array.Resize(ref arStudies, wsPat.Studies.Length - 1);
wsPat.Studies = arStudies;

session.update(wsPat);

The first line may not be necessary ...

Thanks for your help,

Christian

devonl · **Posted:** Wed Jan 17, 2007 8:45 pm

Well for starters you can't just reassign a Collection to a Parent.Collection, that doesn't work. It is more appropriate to do something like Parent.Collection.Remove(object) or RemoveAt(). Since you have cascades set the deletion from the collection will delete the "object".

I also have not used the <array> tag, but in the example you show, you need to set inverse="true" on the <many-to-one>. Since you haven't done that, you are getting the dreaded NULL problem. See the FAQ for more info:

http://www.hibernate.org/359.html#A10

hth,

-devon

chaessig · **Joined:** Tue Jan 16, 2007 5:42 am **Posts:** 4

Hi,

thanks for your advices.

Actually, I know all this, but an Array object does not have a Remove or RemoveAt method ( or, at least, it will throw an NotSupportedException ).
And as I already told, I have to use Arrays. I know it's not the simplest collection object, but I have no other choice in my case.

Concerning the inverse="true", could you be more precise ? I saw in the documentation that inverse="true" is not supported for <array>.

Well, I'm not an easy case :)

Christian

activeperception · **Joined:** Fri May 25, 2007 6:34 am **Posts:** 2

did you manage to find a solution?

I have exactly the same problem: it seems that all-delete-orphan doesn't work for array

russuk · **Joined:** Wed Sep 05, 2007 12:22 pm **Posts:** 8

we also have this issue - has anyone used an <array> collection?