one-to-one mapping and joined subclasses

ToAoM · **Joined:** Mon Feb 23, 2004 1:17 pm **Posts:** 28

I've run into problems with my mappings and a mapping from one class to another class (which is mapped using a joined-subclass).

Mapping for class A:

Code:

<?xml version="1.0"?>
<!DOCTYPE hibernate-mapping PUBLIC
    "-//Hibernate/Hibernate Mapping DTD 2.0//EN" 
    "http://hibernate.sourceforge.net/hibernate-mapping-2.0.dtd">

<hibernate-mapping>
    <class
        name="ClassA"
        dynamic-update="false"
        dynamic-insert="false"
        mutable="true"
    >

        <id name="id" column="ClassAId" type="java.lang.String">
            <generator class="uuid.hex">
            </generator>
        </id>

        <version name="hbmVersion" type="long" column="hbmVersion"            access="field" />

        <one-to-one
            access="field"
            cascade="all"
            class="ClassB"
            name="classB"
            property-ref="classA"
         />
    </class>
</hibernate-mapping>

Mapping for ClassB

Code:

<?xml version="1.0"?>

<!DOCTYPE hibernate-mapping PUBLIC
    "-//Hibernate/Hibernate Mapping DTD 2.0//EN" 
    "http://hibernate.sourceforge.net/hibernate-mapping-2.0.dtd">

<hibernate-mapping>
    <joined-subclass
        name="ClassB"
        extends="ParentOfB"
        dynamic-update="false"
        dynamic-insert="false"
    >
        <key column="ParentOfBId" />
        
        <many-to-one
            class="ClassA"
            unique="true"
            access="property"
            cascade="all"
            property-ref="classB"
            name="ClassA"
         />
    </joined-subclass>
</hibernate-mapping>

The mappingsfile compiles until it reaches the processing of one-to-one relations:

Code:

12:00:51,390 INFO  [Configuration] processing one-to-one association property references
12:00:51,390 INFO  [Configuration] processing foreign key constraints

The error is:

Code:

Caused by: net.sf.hibernate.MappingException: property mapping has wrong number of columns: ClassB.classA type: ClassA
   at net.sf.hibernate.mapping.PersistentClass.validate(PersistentClass.java:269)
   at net.sf.hibernate.mapping.Subclass.validate(Subclass.java:141)
   at net.sf.hibernate.cfg.Configuration.validate(Configuration.java:576)
   at net.sf.hibernate.cfg.Configuration.buildSessionFactory(Configuration.java:733)

Any ideas would be welcome.
-------------------
Hibernate: 2.1.2
Java: 1.4.2_03

ToAoM · **Joined:** Mon Feb 23, 2004 1:17 pm **Posts:** 28

One small error creeped into the mappingsfile above:

Code:

        <many-to-one
            class="ClassA"
            unique="true"
            access="property"
            cascade="all"
            property-ref="classB"
            name="ClassA"
         /> 

should read:

Code:

        <many-to-one
            class="ClassA"
            unique="true"
            access="property"
            cascade="all"
            property-ref="classB"
            name="classA"
         /> 

ToAoM · **Joined:** Mon Feb 23, 2004 1:17 pm **Posts:** 28

I've written a workaround by making these a property in ClassB, a one-to-one in ClassA and manually saving the relation each time. This is far from ideal.

Any other suggestions are still very welcome...

ToAoM · **Joined:** Mon Feb 23, 2004 1:17 pm **Posts:** 28

Just tried with Hibernate 2.1.3 and still seeing this.

emmanuel · **Posted:** Fri Apr 30, 2004 12:45 pm

PArentOfB has a composite ID ?

ToAoM · **Joined:** Mon Feb 23, 2004 1:17 pm **Posts:** 28

It turned out that I still had a foreign-key added to the hbm.xml file. Removing this fixed the problem.