<class name="com.domain.project.models.Category" table="Category">
        <id name="id" type="long" access="property">
            <column name="categoryId" length="20"/>
            <generator class="native"/>
        </id>
        <property name="name" column="categoryName" type="string"/>
        <property name="parentId" column="categoryParentId" type="long"/>
        <bag name="children" table="Category" cascade="save-update, delete" inverse="true" lazy="true"
             fetch="select">
            <key>
                <column name="categoryParentId" not-null="true"/>
            </key>
            <one-to-many class="com.domain.project.models.Category"/>
        </bag>
    </class>

       <many-to-one name="parent" column="categoryParentId" class="com.electronic.commerce.models.Category"
            cascade="all"/>