dynamic-delete

jonigkeit · **Joined:** Thu Dec 21, 2006 7:30 am **Posts:** 11

If have some problem with deletion of subclasses.

The essence of my problem is.

two classes A and B. A is abstract

B extends A

it is mapped as

Code:

<class name="A" table="A">
   <id name="id" type="long" column="ID" />
   <joined-subclass name="B" table="B">
      <key column="ID"/>
   </joined-subclass>
</class>

if I call B.delete() the entry in table B is deleted while the entry in table A stays. Then when hibernate loads all entries of table A, I get an

Code:

InstantiationException: Cannot instantiate abstract class or interface: A

of course.

what I would like would be a tag like

Code:

dynamic-delete

however it does not exist.

So i tried:

Code:

<class name="A" table="A">
   <id name="id" type="long" column="ID" />
   <joined-subclass name="B" table="B">
      <key column="ID"/>
      <sql-delete>
         DELETE FROM B WHERE ID = ?; DELETE FROM A WHERE ID = ?
      </sql-delete>
   </joined-subclass>
</class>

But now i get an other kind of exception, namely:

Code:

Caused by: org.postgresql.util.PSQLException: No value specified for parameter 1.

kochcp · **Posted:** Thu Dec 21, 2006 11:29 am

I think you might just have to create your own delete method which deletes them both with that query in it.

jonigkeit · **Joined:** Thu Dec 21, 2006 7:30 am **Posts:** 11

found a solution -
thx anyway

Javier Martinez · **Posted:** Thu Dec 21, 2006 6:20 pm

And, what is the solution? It's an important issue for my application.

Many thanks in advance.

Regards.

jonigkeit · **Joined:** Thu Dec 21, 2006 7:30 am **Posts:** 11

First of all I use

dynamic-update="true"
dynamic-insert="true"

then I have made sure that references cascade on deletion.

My problem was actually a bit more complicated than I actually described in my simplified code example.

I have a more complex inheritance hierarchy, and the problem was when I deleted one of the subclasses, hibernate would try to delete it superclasses as well, but optimistically.
As another table had a refernce to one of these subclasses and the database was constrained correctly, the database forbid deleting of the superclass object.

Thus I got the InstantiationException.

Here is some of the actual mapping

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">
<!-- Generated 2006-09-26 16:23:20 by Hibernate Tools 3.1.0.beta5 -->
<hibernate-mapping>
   <class name="entity.hibernate.Contactable" table='"Contactable"'
      schema='"public"' lazy="true" abstract="true">
      <id name="id" type="long">
         <column name='"ID"' />
         <generator class="sequence">
            <param name="sequence">"Contactable_ID_seq"</param>
         </generator>
      </id>
      <set name="contacts" table='"ContactList"' lazy="true">
         <key column='"ContactableID"' />
         <many-to-many class="entity.hibernate.Contact">
            <column name='"ContactID"' />
         </many-to-many>
      </set>
      <joined-subclass name="entity.hibernate.Trackable"
         table='"Trackable"' schema='"public"' lazy="true"
         dynamic-update="true" dynamic-insert="true" abstract="true">
         <key column='"ID"' />
         <set name="trackers" inverse="false" lazy="true">
            <key>
               <column name='"TrackableID"' />
            </key>
            <one-to-many class="entity.hibernate.Tracker" />
         </set>
         <joined-subclass name="entity.hibernate.Patient"
            table='"Patient"' schema='"public"' lazy="true"
            dynamic-update="true" dynamic-insert="true">
            <key column='"ID"' />
            <many-to-one name="statusProvider"
               class="entity.hibernate.StatusProvider" fetch="select"
               cascade="delete">
               <column name='"StatusProviderID"' />
            </many-to-one>
            <property name="name" type="string">
               <column name='"Name"' />
            </property>
            <property name="socialSecurityNumber" type="string">
               <column name='"SocialSecurityNumber"' />
            </property>
            <set name="surgeries" inverse="false" lazy="true">
               <key>
                  <column name='"PatientID"' />
               </key>
               <one-to-many class="entity.hibernate.Surgery" />
            </set>
         </joined-subclass>
         <joined-subclass name="entity.hibernate.Personnel"
            table='"Personnel"' schema='"public"' lazy="true"
            dynamic-update="true" dynamic-insert="true">
            <key column='"ID"' />
            <many-to-one name="personnelRole"
               class="entity.hibernate.PersonnelRole" fetch="select">
               <column name='"PersonnelRoleID"' not-null="true" />
            </many-to-one>
            <many-to-one name="statusProvider"
               class="entity.hibernate.StatusProvider" fetch="select"
               cascade="delete">
               <column name='"StatusProviderID"' />
            </many-to-one>
            <many-to-one name="securityContext"
               class="entity.hibernate.SecurityContext" fetch="select"
               not-null="true" cascade="delete">
               <column name='"SecurityContextID"' />
            </many-to-one>
            <property name="name" type="string">
               <column name='"Name"' />
            </property>
            <property name="userName" type="string">
               <column name='"UserName"' not-null="true" />
            </property>
            <property name="password" type="string">
               <column name='"Password"' not-null="true" />
            </property>
            <many-to-one name="image" class="entity.hibernate.Image"
               fetch="select">
               <column name='"ImageID"' />
            </many-to-one>
            <property name="abbreviatedName" type="string">
               <column name='"AbbreviatedName"' />
            </property>
            <property name="active" type="boolean">
               <column name='"Active"' not-null="true" />
            </property>
            <joined-subclass name="entity.hibernate.Substitute"
               table='"Substitute"' schema='"public"' lazy="true"
               dynamic-update="true" dynamic-insert="true">
               <key column='"ID"' />
               <property name="substitute" type="boolean">
                  <column name='"IsSubstitute"' not-null="true" />
               </property>
            </joined-subclass>
         </joined-subclass>
      </joined-subclass>
      <joined-subclass name="entity.hibernate.Location"
         table='"Location"' schema='"public"' lazy="true"
         dynamic-update="true" dynamic-insert="true">
         <key column='"ID"' />
         <property name="shortText" type="string">
            <column name='"ShortText"' />
         </property>
         <property name="longText" type="string">
            <column name='"LongText"' />
         </property>
         <set name="videoFeeds" inverse="false" lazy="true">
               <key>
                  <column name='"LocationID"' not-null="true" />
               </key>
               <one-to-many class="entity.hibernate.VideoFeed" />
            </set>
         <joined-subclass name="entity.hibernate.SurgeryRoom"
            table='"SurgeryRoom"' schema='"public"' lazy="true"
            dynamic-update="true" dynamic-insert="true">
            <key column='"ID"' />
            <property name="type" type="string">
               <column name='"Type"' />
            </property>
            <many-to-one name="ongoingSurgery"
               class="entity.hibernate.Surgery" fetch="select">
               <column name='"OngoingSurgeryID"' />
            </many-to-one>
            <property name="text" type="string">
               <column name='"Text"' />
            </property>
            <set name="teams" inverse="false" lazy="true">
               <key>
                  <column name='"SurgeryRoomID"' not-null="true" />
               </key>
               <one-to-many class="entity.hibernate.Team" />
            </set>
            <set name="surgeries" inverse="false" lazy="true">
               <key>
                  <column name='"SurgeryRoomID"' not-null="true" />
               </key>
               <one-to-many class="entity.hibernate.Surgery" />
            </set>
         </joined-subclass>
      </joined-subclass>
   </class>
</hibernate-mapping>

Inheritance is achived using "Table per subclass"