Delete children

rafaelsantini · **Posted:** Wed Jan 20, 2010 3:39 pm

I have an one-to-one association implemented as many-to-one with an unique constraint on the foreign key. The cascade property is "all". I expect that the children been deleted when the parent is set to null. But the children isn't deleted. How can I to do?

Mapping:

Code:

<class name="Student">
  <id name="id">
    <generator class="native"/>
  </id>
  <property name="name" not-null="true"/>
  <many-to-one name="attach" column="id_attach" unique="true" cascade="all"/>   
</class>

<class name="Attach">
  <id name="id">
    <generator class="native"/>
  </id>   
</class>

Code:

Code:

student.setAttach(null);
session.saveOrUpdate(obj);

The column id_attach is set to null in database, but the record isn't dropped from Attach table.

I wasted the day trying figure out why the record is not deleted!

Cameron McKenzie · **Posted:** Thu Jan 21, 2010 9:47 am

Well, nullifying the association only implies that the association is deleted, right? Why not actually delete the entity? Give it a try!

rafaelsantini · **Posted:** Thu Jan 21, 2010 1:55 pm

Suppose a CRUD application in JSF. The user edits the Student and clicks on "Delete attach" button. Then, the action do: student.setAttach(null). After, the user clicks on the "Save record" button. Now, how can I know what attach was referenced? I will need keep the reference.

The Attach is a weak entity. So, I would not like to implement a Attach Dao to delete the entity manually. See the code that I need to implement for every entity that has an association that can be deleted:

Code:

public void deleteAttach() {    
    Attach attachToBeDeleted = getPersistentObject().getAttach();
    getPersistentObject().setAttach(null);    
}

public String saveRecord() {
   ...
   if (attachToBeDeleted != null) {
       attachDao.makeTransient(attachToBeDeleted );    
   }
}

Is suck write this kind of code everywhere.

Why Hibernate can't delete the attach entity if the association was deleted?

Thank you!