Re: [Sculptor] uni-directional one-to-many mapping?

Hi Patrik,

Yup, that's what we tried.  We ran into a problem though.  Here's the definition:

                Entity PropertyData {
                   - List<@PropertyItem> items fetch="join" cascade="all" inverse
                }
               
                ValueObject PropertyItem {
                        String stuff nullable
                }

When we did that, it created the correct one-to-many Hibernate mapping like this:

<hibernate-mapping default-cascade="none" default-access="property" default-lazy="true" auto-import="true">
        <class name="com.foo.PropertyData" table="OM_PROPERTY_DATA" mutable="true" polymorphism="implicit" dynamic-update="false" dynamic-insert="false" select-before-update="false" optimistic-lock="version">
                ...
                <list name="items" inverse="true" cascade="all" fetch="join" lazy="false" mutable="true" optimistic-lock="true" embed-xml="true">
                        <key column="C_PROPERTY_DATA" on-delete="noaction"/>
                        <index column="C_ITEM_INDEX"/>
                        <one-to-many class="com.foo.PropertyItem" not-found="exception" embed-xml="true"/>
                </list>
        </class>
</hibernate-mapping>


Then when we saved a PropertyData with PropertyItems, Hibernate created all the PropertyData and PropertyItem records, but the C_PROPERTY_DATA foreign key column in PropertyItem was null.  So when we retrieve the PropertyData again, it does not have any PropertyItems attached to it.  Isn't "inverse" in Hibernate only used for bi-directional relationships?  How does the C_PROPERTY_DATA key get set?

Please let me know if I broke something or if we are doing something wrong.

Thanks!
--Polly

Patrik Nordwall wrote:

Do you need something like this, i.e. Moon doesn't refer back to Planet?

Entity Planet {
   - @Set<Moon> moons
}

Entity Moon {
}


This will result in a uni-directional many association, but will be implemented in the database as many-to-many.

To implement it with an ordinary foreign key in the child table you have to add inverse

Entity Planet {
   - @Set<Moon> moons inverse
}

Doc: http://www.fornax-platform.org/cp/display/fornax/3.+Advanced+Tutorial+(CSC)#3.AdvancedTutorial(CSC)-AdditionalReferenceFeatures

/Patrik