Simple One to Many not working in Hibernate

[Darren Carter]

Hi Everyone,

I really hope someone could help as I been struggling with an issue with hibernate and a spring mvc app. I must be doing something silly and was hoping someone could help.

I have the following relationships


1) SiteMenu has many MenuSection
2) SiteMenu has one Site
2) MenuSection has Many Products


I simply trying to retrieve a SiteMenu object which contains all the MenuSecions and associated Products. However when I add the products to my hibernate mapping (MenuSection.hbm), I receive duplicate MenuSection objects in my query. Removing the products association returns the correct number of MenuSections.

Here are the Hibernate Mappings

<hibernate-mapping>
    <class name="uk.co.mycompany.persistence.model.SiteMenu" table="site_menu" catalog="test_db">
        <id name="id" type="int" column="id">
            <generator class="identity" />
        </id>
        <many-to-one name="site" class="uk.co.mycompany.persistence.model.Site" fetch="select">
            <column name="site_id" not-null="true" />
        </many-to-one>
        <property name="name" type="string">
            <column name="name" length="45" not-null="true" />
        </property>
        <property name="description" type="string">
            <column name="description" length="45" not-null="true" />
        </property>
        <bag name="menuSections" inverse="true" cascade="all" fetch="join">
            <key column ="site_menu_id" />
            <one-to-many class="uk.co.mycompany.persistence.model.MenuSection" />
        </bag>
    </class>
</hibernate-mapping>

<hibernate-mapping>
    <class name="uk.co.mycompany.persistence.model.MenuSection" table="menu_section" catalog="test_db">
        <id name="id" type="int" column="id">
            <generator class="assigned" />
        </id>
        <many-to-one name="siteMenu" class="uk.co.mycompany.persistence.model.SiteMenu" fetch="select">
            <column name="site_menu_id" not-null="true" />
        </many-to-one>
        <property name="name" type="string">
            <column name="name" length="45" not-null="true" />
        </property>
        <property name="description" type="string">
            <column name="description" length="45" not-null="true" />
        </property>
        <list name="products" inverse="true"  cascade="all" fetch="join" outer-join="false"  >
            <key column ="menu_section_id" />
            <list-index column="product_position"/>
            <one-to-many class="uk.co.mycompany.persistence.model.Product" />
        </list>
    </class>
</hibernate-mapping>

<hibernate-mapping>
    <class name="uk.co.mycompany.persistence.model.Product" table="product" catalog="test_db">
        <id name="id" type="int" column="id">
            <generator class="assigned" />
        </id>
        <many-to-one name="menuSection" class="uk.co.mycompany.persistence.model.MenuSection" fetch="join">
            <column name="menu_section_id"/>
        </many-to-one>
        <property name="name" type="string">
            <column name="name" length="45" not-null="true" />
        </property>
        <property name="description" type="string">
            <column name="description" length="45" not-null="true" />
        </property>
        <property name="size" type="string">
            <column name="size" length="1" not-null="true" />
        </property>
        <property name="price" type="byte">
            <column name="price" precision="2" scale="0" not-null="true" />
        </property>
    </class>
</hibernate-mapping>

Here is my Criteria query

return (SiteMenu) currentSession()
				.createCriteria(SiteMenu.class)
				.setResultTransformer(Criteria.DISTINCT_ROOT_ENTITY)
				.createAlias("site", "site")
				.add(Restrictions.eq("site.name", site.getName()))
				.uniqueResult();

Why is it if I introduce products it duplicates the records returned? Can some please help as I am not sure what to do?

Best Regards