Moving a child object to a different parent

jelmerk · **Joined:** Tue Sep 13, 2005 6:34 pm **Posts:** 3

I am using hibernate 3 and I have a category object mapped with the hibernate mapping included at the bottom of this post

It has among others the following methods :

public void removeChildCategory(Category category){
if (category == null) {
throw new IllegalArgumentException("Category to be removed from category is null");
}
category.setParentCategory(null);
childCategories.remove(category);
}

public void addChildCategory(Category category){
if (category == null) {
throw new IllegalArgumentException("Category to be added to category is null");
}
category.setParentCategory(this);
childCategories.add(category);
}

The problem is that when i try to move one category to another

like this

Code:

booksCat.removeChildCategory(thrillersCat);
moviesCat.addChildCategory(thrillersCat);

I get the following exception

org.hibernate.ObjectDeletedException: deleted object would be re-saved by cascade (remove deleted object from associations): [com.zenggi.data.Category#379]

I am kind of at a loss as to why this is occuring since the parent field has cascade set to none and the item got removed from the first collection
can anyone offer some insight ?

Code:

<?xml version="1.0"?>
<!DOCTYPE hibernate-mapping PUBLIC
    "-//Hibernate/Hibernate Mapping DTD 3.0//EN"
    "http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">

<hibernate-mapping package="com.company">


<class name="Category"
      table="CATEGORY"
      lazy="true">

   <id name="id"
      type="long"
      column="ID"
      unsaved-value="null">
      <generator class="identity"/>
   </id>

    <version name="version" column="VERSION" type="integer"/>

    <property name="name" type="string">
        <column name="NAME" not-null="true"/>
    </property>

    <property name="description" type="string">
        <column name="DESCRIPTION" />
    </property>

    <many-to-one name="parentCategory"
                 class="Category"
                 lazy="false"
                 insert="false"
                 update="false"
                 cascade="none">
        <column name="PARENT_CATEGORY_ID"
                not-null="false" />
    </many-to-one>

    <list   name="childCategories"
            lazy="false"
            cascade="all-delete-orphan"
            inverse="false">
        <key column="PARENT_CATEGORY_ID"/>
        <list-index column="CATEGORY_INDEX" />
        <one-to-many class="Category"/>
    </list>

</class>

</hibernate-mapping>

christian · **Posted:** Sun Nov 13, 2005 5:06 pm

http://forum.hibernate.org/viewtopic.php?t=936040

christian · **Posted:** Sun Nov 13, 2005 5:10 pm

http://opensource2.atlassian.com/projec ... se/HHH-785

jelmerk · **Joined:** Tue Sep 13, 2005 6:34 pm **Posts:** 3

Christian thanks for your prompt response, could you perhaps elaborate a bit on the "complex session coding" you are refering to in the jira issue.

christian · **Posted:** Sun Nov 13, 2005 7:04 pm

I did, in fact, there is a whole book about it and hundreds of pages of documentation. Read up on orphan-delete and delete operations.

christian · **Posted:** Sun Nov 13, 2005 7:05 pm

The "complex" was for my particular use case, by the way. Yours is trivial. Don't use orphan-delete.

hhuber · **Posted:** Mon Nov 14, 2005 6:04 am

jelmerk wrote:

...

Code:

booksCat.removeChildCategory(thrillersCat);
moviesCat.addChildCategory(thrillersCat);

I get the following exception

org.hibernate.ObjectDeletedException: deleted object would be re-saved by cascade (remove deleted object from associations): [com.zenggi.data.Category#379]

I am kind of at a loss as to why this is occuring since the parent field has cascade set to none and the item got removed from the first collection
can anyone offer some insight ?

Code:

<?xml version="1.0"?>
<!DOCTYPE hibernate-mapping PUBLIC
    "-//Hibernate/Hibernate Mapping DTD 3.0//EN"
    "http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">

<hibernate-mapping package="com.company">


<class name="Category"
      table="CATEGORY"
      lazy="true">

   <id name="id"
      type="long"
      column="ID"
      unsaved-value="null">
      <generator class="identity"/>
   </id>

    <version name="version" column="VERSION" type="integer"/>

    <property name="name" type="string">
        <column name="NAME" not-null="true"/>
    </property>

    <property name="description" type="string">
        <column name="DESCRIPTION" />
    </property>

    <many-to-one name="parentCategory"
                 class="Category"
                 lazy="false"
                 insert="false"
                 update="false"
                 cascade="none">
        <column name="PARENT_CATEGORY_ID"
                not-null="false" />
    </many-to-one>

    <list   name="childCategories"
            lazy="false"
            cascade="all-delete-orphan"
            inverse="false">
        <key column="PARENT_CATEGORY_ID"/>
        <list-index column="CATEGORY_INDEX" />
        <one-to-many class="Category"/>
    </list>

</class>

</hibernate-mapping>

I don't think that the problem comes from the mapping of the parent field.

I rather believe, it's the mapping of the list. There you have cascade="all-delete-orphan". AFAIK, this means that an object should be deleted, when it's removed from the collection.
On the other hand, you add the object to the collection of another parent where it is to be stored in the database.

If I understand Hibernate and your case right, you must not use "delete-orphan" in this case. AFAIK, you may only use it, if the objects within the collection really cease to exist, when they're removed from the collection.