<hibernate-mapping package="*.*.*.objects">
    <class name="Complaint" table="COMPLAINTS">
        <id name="id" column="ID" access="field">
            <generator class="org.hibernate.id.enhanced.SequenceStyleGenerator">
                <param name="sequence_name">SSEQUENCE</param>
            </generator>
        </id>
        ...
        <many-to-one name="declarant" lazy="proxy" unique="true" class="*.*.*.objects.Declarant" cascade="all-delete-orphan">
            <column name="DECLARANT_ID" not-null="true"/>
        </many-to-one>
        ...
    </class>
</hibernate-mapping>

<hibernate-mapping package="*.*.*.objects">
    <class name="Declarant" table="COMPL_DECL_LINKS">
        <!--<cache usage="read-write"/>-->
        <id name="id" column="ID" access="field">
            <generator class="org.hibernate.id.enhanced.SequenceStyleGenerator">
                <param name="sequence_name">SSEQUENCE</param>
            </generator>
        </id>
        <discriminator column="DECL_TYPE" type="string" length="2"/>
        <subclass name="JuridicalPerson" discriminator-value="UL">
            <join table="UL">
                <key column="DECL_ID"/>
                <property name="title" column="TITLE"/>
                <property name="INN" column="INN" length="10"/>
                <property name="KPP" column="KPP" length="9"/>
                <property name="largestTaxpayer" column="LARGETAXPAYER"/>
            </join>
        </subclass>
        <subclass name="PhysicalPerson" discriminator-value="FL">
            <join table="FL">
                <key column="DECL_ID"/>
                <property name="INN" column="INN" length="12"/>
                <property name="firstname" column="FIRSTNAME"/>
                <property name="surname" column="SURNAME"/>
                <property name="patronymic" column="PATRONYMIC"/>
            </join>
        </subclass>
    </class>
</hibernate-mapping>