hibernate 持久化

Question

现有Class Check,ManagerCheck,MDCheck.其中ManagerCheck 和 MDCheck继承Check，每个子类一张表(Table per subclass)映射。
数据库有一条Check记录和其通过主键关联的ManagerCheck，现在我想新建一个MDCheck并持久化该怎么做？

Answer 1

问题补充：我new 一个MDCheck ，但我saveOrUpdate时出错
2011-1-28 11:21:57 org.hibernate.event.def.AbstractFlushingEventListener performExecutions
严重: Could not synchronize database state with session
org.hibernate.StaleObjectStateException: Row was updated or deleted by another transaction (or unsaved-value mapping was incorrect):其中ManagerCheck 和MDCheck中都有一个TimeStamp属性  

Answer 2

<class name="Check" table="t_check" catalog="pfa">
        <id name="checkId" column="app_id">
            <generator class="foreign">
            <param name="property">appForm</param>
         </generator>
        </id>
    <one-to-one name="appForm"  lazy="false"
        constrained="true"/>         
        <many-to-one name="state" class="FormState" lazy="false">
            <column name="state_id" />
        </many-to-one>
        <property name="curLv" type="java.lang.Integer">
            <column name="curLv" />
        </property>
        
        <property name="reworkReason" type="java.lang.String">
            <column name="reason" />
        </property>
        
        <property name="lv" type="java.lang.Integer">
            <column name="Lv" />
        </property>
        <property name="lastProccess" type="java.lang.Integer">
            <column name="lastProccess" />
        </property>
        
        <joined-subclass name="ManagerCheck" table="t_mgrCheck">
         <key column ="app_id"/>
<property name="reason" type="java.lang.String" column="reason"></property>
<property name="time" type="java.sql.Timestamp" column="check_time"></property>
<!-- 映射和Operation之间的关联关系 -->
<many-to-one name="operate" column="operate_id"
class="Operation" lazy="false"/>
</joined-subclass>

<joined-subclass name="ManagerDirectorCheck" table="t_mdCheck">
<key column="app_id"/>
<property name="reason" type="java.lang.String" column="reason"/>
<property name="time" type="java.sql.Timestamp" column="check_time"></property>
<!-- 映射和Operation之间的关联关系 -->
<many-to-one name="operate" column="operate_id"
class="Operation" lazy="false"/>
</joined-subclass>

<joined-subclass name="MDDirectorCheck" table="t_mddCheck">
<key column="app_id"/>
<property name="reason" type="java.lang.String" column="reason"/>
<property name="time" type="java.sql.Timestamp" column="check_time"></property>
<!-- 映射和Operation之间的关联关系 -->
<many-to-one name="operate" column="operate_id"
class="Operation" lazy="false"/>
</joined-subclass>

<joined-subclass name="PCDirectorCheck" table="t_pcdCheck">
<key column="app_id"/>
<property name="reason" type="java.lang.String" column="reason"/>
<property name="time" type="java.sql.Timestamp" column="check_time"></property>
<!-- 映射和Operation之间的关联关系 -->
<many-to-one name="operate" column="operate_id"
class="Operation" lazy="false"/>
</joined-subclass>
    </class>

Answer 3

Check check=checkDao.get(checkId);
ManagerCheck mcheck=(ManagerCheck)mcheckDao.get(AppId)
if(mcheck!=null)
{
   mcheck.setOperate(operate);
   mcheck.setReason(reason);
   mcheck.setTime(new Timestamp(System.currentTimeMillis()));
   mcheck.setCurLv(MANAGERDIRECTOR_LV);
mcheckDao.saveOrupdate(mcheck);
ManagerDirectorCheck mdCheck=new ManagerDirectorCheck(check);
mdCheck.setTime(mcheck.getTime());
mdcheckDao.saveOrupdate(mdCheck);
}