hibernate 集成映射

    <class name="Worker" table="worker" discriminator-value="worker">

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

        <discriminator column="type" type="string"></discriminator>

        <property name="name"></property>

        <subclass name="Driver" discriminator-value="driver">
            <property name="car"></property>
        </subclass>
    </class>

    <class name="Animal" table="animal">

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

        <property name="name"></property>

        <joined-subclass name="Cat" table="cat">
            <key column="cat_id"></key>
            <property name="food"></property>
        </joined-subclass>
    </class>

    <class name="Book" table="book">

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

        <property name="name"></property>

        <union-subclass name="English" table="english">
            <property name="language"></property>
        </union-subclass>

    </class>