Using joined-subclass and suclass

sigrist · **Posted:** Thu Aug 25, 2005 8:44 am

Hello guys.

I need to map my class using these strategies, joined-subclass and sucblass, so, I did this:

Code:

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

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

<hibernate-mapping>
    <class
        name="com.mypackage.MySuperClass"
        table="my_superclass_table"
    >

        <id
            name="id"
            column="id"
            type="java.lang.Integer"
        >
            <generator class="increment"/>
        </id>

        <discriminator
            column="type_class_name"
        />

        <property
            name="defaultValue"
            type="java.lang.String"
            update="true"
            insert="true"
            column="default_value"
        />
        
        <subclass
          name="com.mypackage.MySubClass"/>          
          
      <joined-subclass
         name="com.mypackage.MyJoinedSubClass"
         table="my_joinedsubclass_table"
      >
         <key
         />
            <property
               name="color"
               type="java.lang.String"
               update="true"
               insert="true"
               column="color"
            />
      </joined-subclass>
    </class>    
</hibernate-mapping>

But when I try to star my application, I receive this error message:

Code:

Caused by: org.xml.sax.SAXParseException: The content of element type "class" must match "(meta*,subselect?,cache?,synchronize*,comment?,(id|composite-id),discriminator?,natural-id?,(version|timestamp)?,(property|many-to-one|one-to-one|component|dynamic-component|properties|any|map|set|list|bag|idbag|array|primitive-array|query-list)*,((join*,subclass*)|joined-subclass*|union-subclass*),loader?,sql-insert?,sql-update?,sql-delete?,filter*)".

Can´t I have subclass mapping with joined-subclass?

Thanks
Sigrist

nathanmoon · **Posted:** Thu Aug 25, 2005 10:19 am

Nope. From the docs:

Quote:

Hibernate does not support mixing <subclass>, and <joined-subclass> and <union-subclass> mappings under the same root <class> element.

[/quote]

Dmitri Rasnitsyn · **Posted:** Thu Aug 25, 2005 10:33 am

Sigrist,

sorry, but subclass and joint-subclass are incompatible.

subclass assumes a table per class hierarchy (look at Hibernate Reference, 3.0.5 #10.1.1), i.e. one table contains all attributes of the subclass and the superclass[es]

joined-subclass assumes a table per subclass (i.e. attributes of the class and each its subclass are stored in different tables). (#10.1.2 in the same reference).

If you try to mix them how would hibernate know whether to look for one talbe or multiple tables?

I belive this is the reason the XSD allows yo to define either join and subclass OR joined-subclass OR union-subclass: ((join*,subclass*)|joined-subclass*|union-subclass*),

You can try to full the parser by defining each subclass in a different mapping file:

<hibernate-mapping package="...">
<subclass
name="com.mypackage.MySubClass"
extends ="com.mypackage.MySuperClass">
...
</subclass>
</hibernate-mapping>

another file:

<hibernate-mapping package="...">
<joined-subclass
name="com.mypackage.MyJoinedSubClass"
table="my_joinedsubclass_table"
extends ="com.mypackage.MySuperClass">
...
</joined-subclass>
</hibernate-mapping>

But I doubt it will work because of the above concern...

Dmitri

sigrist · **Posted:** Thu Aug 25, 2005 10:42 am

Thanks nathanmoon.

We were making confusion with tags here....

emmanuel · **Posted:** Thu Aug 25, 2005 6:47 pm

Use <join in <subclass to mix both strategies

priyankaMahajan · **Joined:** Mon Oct 12, 2009 6:07 am **Posts:** 7

I am using join inside subclass but Now I need to defins the mapping for list inside join tag,

which hibernate does not allow. Can you help me in this?

<subclass name="foo">
<join table="foo">

<key..
<property..
<list???????
</join>
</subclass>