Class discriminator not being picked up

cowwoc · **Joined:** Tue Mar 02, 2004 6:17 pm **Posts:** 151

I get this exception on startup:

Code:

org.hibernate.MappingException: No discriminator found for com.be.desktopbeautifier.server.DefaultTheme. Discriminator is needed when 'single-table-per-hiearchy' is used and a class has subclasses

Here is my mapping file:

Code:

<?xml version="1.0" encoding="UTF-8"?>

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

<hibernate-mapping
>
    <class
        name="com.be.desktopbeautifier.server.AbstractTheme"
        table="theme"
        discriminator-value="AbstractTheme"
    >

        <id
            name="id"
            column="id"
            type="int"
            unsaved-value="0"
        >
            <generator class="native">
              <!--  
                  To add non XDoclet generator parameters, create a file named 
                  hibernate-generator-params-AbstractTheme.xml 
                  containing the additional parameters and place it in your merge dir. 
              --> 
            </generator>
        </id>

        <version
            name="version"
            column="version"
            type="int"
        />

        <set
            name="children"
            lazy="false"
            cascade="all"
            sort="unsorted"
        >

            <key
            >
                <column
                    name="parent_id" 
                    not-null="true"
                />
            </key>

            <one-to-many
                  class="com.be.desktopbeautifier.server.AbstractTheme"
            />
        </set>

        <property
            name="name"
            type="java.lang.String"
            update="true"
            insert="true"
            column="name"
            not-null="true"
        />

        <!--
            To add non XDoclet property mappings, create a file named
                hibernate-properties-AbstractTheme.xml
            containing the additional properties and place it in your merge dir.
        -->
        <subclass
            name="com.be.desktopbeautifier.server.DefaultTheme"
            discriminator-value="DefaultTheme"
        >

       <!--
               To add non XDoclet property mappings, create a file named
                hibernate-properties-DefaultTheme.xml
      containing the additional properties and place it in your merge dir.
       -->
        </subclass>
    </class>
</hibernate-mapping>

Clearly "discriminator-value" is specified. Any ideas why this does not work?

Thank you,
Gili

sven · **Posted:** Mon Apr 18, 2005 1:09 pm

I think you missed to define the discriminator column.

For example:

Code:

See 5.1.6 in the documentation.

Best regards
Sven

cowwoc · **Joined:** Tue Mar 02, 2004 6:17 pm **Posts:** 151

sven wrote:

I think you missed to define the discriminator column.

For example:

Code:

See 5.1.6 in the documentation.

Best regards
Sven

Odd, that did it. Thanks!

The funny thing is that both in Hibernate Annotations and XDoclet, if you don't specify the discriminator a default value is supposed to get used. The column is supposed to default to "type" and the value to the fully-qualified name of the class. For some reason, however, when using XDoclet you are required to specify these values manually.

Gili

emmanuel · **Posted:** Mon Apr 18, 2005 1:50 pm

If you don't specify the column attribute in HBM, the column name equals to "class".
If you don't specify the @DiscriminatorColumn using annotations, the column name equals to "TYPE".

discrimiantor value default to the fully qualified class name.

cowwoc · **Joined:** Tue Mar 02, 2004 6:17 pm **Posts:** 151

emmanuel wrote:

If you don't specify the column attribute in HBM, the column name equals to "class".
If you don't specify the @DiscriminatorColumn using annotations, the column name equals to "TYPE".

discrimiantor value default to the fully qualified class name.

Right, but the question is what happens if you don't specify the discriminator in the mapping file? That is, do the defaults get applied by Hibernate or by the Annotations/XDoclet layer? My guess is the latter.

Thanks,
Gili

emmanuel · **Posted:** Tue Apr 19, 2005 2:09 pm

There is not discriminator default for the hbm layer.