<?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="org.ConcreateClass"
        table="ConcreateClass" >

        <id name="id" column="id" type="java.lang.Long" >
            <generator class="native"> </generator>
        </id>

        <property
            name="miscField"
            type="java.lang.String"
            update="true"
            insert="true"
            column="miscField"
            length="50"
        />

        <map name="attrs" table="dm_attributes" lazy="true" sort="unsorted" cascade="all" >
            <key column="documentId" />
            <index column="map_key" type="string" />
            <element column="map_value" type="string" not-null="true" unique="false"/>
        </map>

    </class>

</hibernate-mapping>

Session sessionGET = HibernateUtil.currentSession();
        Transaction txGET = sessionGET.beginTransaction();
request =(ConcreateClass) sessionGET.load(ConcreateClass.class, theID);
request.addAttr("key1", "value1");
        request.setMiscField("update");
        sessionGET.saveOrUpdate(request);
        txGET.commit();
        HibernateUtil.closeSession();      

(org.ConcreateClassTest)org.hibernate.exception.ConstraintViolationException: Could not execute JDBC batch update
   at org.hibernate.exception.ErrorCodeConverter.convert(ErrorCodeConverter.java:74)
   at org.hibernate.exception.JDBCExceptionHelper.convert(JDBCExceptionHelper.java:43)
   at org.hibernate.jdbc.AbstractBatcher.executeBatch(AbstractBatcher.java:181)
   at org.hibernate.engine.ActionQueue.executeActions(ActionQueue.java:226)
   at org.hibernate.engine.ActionQueue.executeActions(ActionQueue.java:139)
   at org.hibernate.event.def.AbstractFlushingEventListener.performExecutions(AbstractFlushingEventListener.java:274)
   at org.hibernate.event.def.DefaultFlushEventListener.onFlush(DefaultFlushEventListener.java:27)
   at org.hibernate.impl.SessionImpl.flush(SessionImpl.java:730)
   at org.hibernate.impl.SessionImpl.managedFlush(SessionImpl.java:324)
   at org.hibernate.transaction.JDBCTransaction.commit(JDBCTransaction.java:86)
   at org.ConcreateClassTest.testHibernate1(ConcreateClassTest.java:75)
   at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
   at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
   at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
   at org.ConcreateClassTest.main(ConcreateClassTest.java:30)
Caused by: java.sql.BatchUpdateException: Cannot add or update a child row: a foreign key constraint fails
   at com.mysql.jdbc.ServerPreparedStatement.executeBatch(ServerPreparedStatement.java:642)
   at org.hibernate.jdbc.BatchingBatcher.doExecuteBatch(BatchingBatcher.java:57)
   at org.hibernate.jdbc.AbstractBatcher.executeBatch(AbstractBatcher.java:174)

private Map attrs = new HashMap();
   /**
     * @hibernate.map lazy="true" table="dm_attributes" cascade="all"
     * @hibernate.collection-index column="map_key" type="string"
     * @hibernate.collection-key column="documentId" type="string"
     * @hibernate.collection-element type="string" column="map_value" not-null="true"
    */
   public Map getAttrs() {
      return attrs;
   }
   public void setAttrs(Map attrs) {
      this.attrs = attrs;
   }
   public void addAttr(String key, String value) {
      if (attrs == null) {
         attrs = new HashMap();
      }
      attrs.put(key, value);
   }   
   public Object getAtt(String key) {
      if (attrs == null) {
         return null;
      }
      return attrs.get(key);
   }