<hibernate-mapping package="org.hyperic.hq.authz.server.session">

  <class name="Resource" table="EAM_RESOURCE" lazy="true">
   
   <!-- 缓存usage(必须)说明了缓存的策略 -->
    <cache usage="read-write"/>
 
 <!-- name指类中的变量 -->
    <id name="id" type="integer">
     <!-- column指表中的字段 -->
      <column name="ID" not-null="true"/>
      
      <!-- generator是一个生成器，用来为id分配值 -->
      <generator class="org.hyperic.hibernate.id.ComboGenerator">
        <param name="sequence">EAM_RESOURCE_ID_SEQ</param>
      </generator>

      或者是

      <generator class="identity"></generator>

    </id>
 <!-- 实现乐观锁要在表中添加版本控制字段  乐观锁就是跟事务有关
  比如：两个事务的提交，第二个比第一个提交的版本旧就会报异常
 
 -->
    <version name="_version_" type="long">
      <column name="VERSION_COL" default="0"/>
    </version>
 
 <!-- 在数据库表中有体现，多对一，外键，对应ResourceType表
 一对多在类中的类型就是对应的类
 -->
    <many-to-one name="resourceType" class="ResourceType">
      <column name="RESOURCE_TYPE_ID" not-null="false"/>
    </many-to-one>

    <property name="instanceId" type="integer">
   <!--  index是索引字段 -->
      <column name="INSTANCE_ID" not-null="false" index="EAM_RESOURCE_INSTANCE_ID_IDX"/>
    </property>

    <many-to-one name="owner" class="AuthzSubject">
      <column name="SUBJECT_ID" not-null="false" index="EAM_RESOURCE_OWNER_ID_IDX"/>
    </many-to-one>

    <many-to-one name="prototype">
      <column name="PROTO_ID" not-null="true" index="EAM_RESOURCE_PROTO_IDX"/>
    </many-to-one>

    <property name="name" type="string">
      <column name="NAME" not-null="false" length="500"/>
    </property>

    <property name="sortName" type="string">
      <column name="SORT_NAME" not-null="false" length="500"/>
    </property>

    <property name="system" type="boolean">
      <column name="FSYSTEM" not-null="false"/>
    </property>

    <property name="mtime" type="long">
      <column name="MTIME" default="0"/>
    </property>

 <!-- 集合映射
 name为resource类中的变量
 EAM_RES_GRP_RES_MAP为映射的表
 key为EAM_RES_GRP_RES_MAP表中的RESOURCE_ID字段对应resource的id
 -->
    <bag inverse="true" cascade="all-delete-orphan" name="groupBag" table="EAM_RES_GRP_RES_MAP">
      <cache usage="read-write"/>
      <key column="RESOURCE_ID"/>
      <one-to-many class="GroupMember"/>
    </bag>

    <bag inverse="true" cascade="all-delete-orphan" name="virtuals" table="EAM_VIRTUAL">
      <key on-delete="cascade" column="RESOURCE_ID"/>
      <one-to-many class="Virtual"/>
    </bag>

    <!-- We primarily only want this bag so that Hibernate can use HQL joins
         for us.  It should not be used from code -->
    <bag inverse="true" cascade="none" name="fromEdges" table="EAM_RESOURCE_EDGE">
      <key on-delete="cascade" column="FROM_ID"/>
      <one-to-many class="ResourceEdge"/>
    </bag>
   
    <bag inverse="true" cascade="none" name="toEdges" table="EAM_RESOURCE_EDGE">
      <key on-delete="cascade" column="TO_ID"/>
      <one-to-many class="ResourceEdge"/>
    </bag>
  </class>

</hibernate-mapping>