Simple relational mapping problem

UngaWunga · **Joined:** Wed Feb 04, 2009 6:13 pm **Posts:** 1

I've gone through the documentation and the sample code, and just haven't been able to figure out the problem with my mapping file. Any help would be appreciated.

Hibernate version: 2.0.1.4000

Mapping documents:

Code:

    <class name="ProviderTitle" table="ProviderTitle" lazy="true">
        <id name="ProviderTitleId" column="providerTitleID" type="Guid">
            <generator class="guid.comb" />
        </id>

       <one-to-one name="ProviderTitleDetail"
                    class="EBSCO.DDP.TitleRepository.Core.Entity.ProviderTitleDetail,TitleRepository.Core"
                    cascade="all"
                    constrained="true"
                    property-ref="ProviderTitle"  />
    </class>


    <class name="ProviderTitleDetail" table="ProviderTitleDetail" lazy="true">
        <id name="ProviderTitleDetailId" column="providerTitleDetailID" type="Guid">
            <generator class="guid.comb" />
        </id>

        <one-to-one name="ProviderTitle" cascade="save-update" foreign-key="providerTitleID" />
        <!--<many-to-one name="ProviderTitle" column="providerTitleID" cascade="save-update" not-null="true" />-->

        <property name="Detail" column="detail" type="string" not-null="true" />
    </class>

Code between sessionFactory.openSession() and session.close():

Code:

            using( ISession session = _sessionManager.OpenSession() )
            {
                providerTitle = new ProviderTitle();
                ProviderTitleDetail ptd = new ProviderTitleDetail( titleDescription.ProviderDetail );
                providerTitle.ProviderTitleDetail = ptd;

                session.SaveOrUpdate( providerTitle );
                session.Flush();
            }

Name and version of the database you are using: SqlServer2005

The database tables are as such:

Code:

[dbo].[ProviderTitle](
   [providerTitleID] [uniqueidentifier] NOT NULL
)

[dbo].[ProviderTitleDetail](
   [providerTitleDetailID] [uniqueidentifier] NOT NULL,
   [providerTitleID] [uniqueidentifier] NOT NULL,
   [detail] [xml] NOT NULL,
)

The exception I'm getting is: "Cannot insert the value NULL into column 'providerTitleID', table 'DevTitle.dbo.ProviderTitleDetail'; column does not allow nulls. INSERT fails.\r\nThe statement has been terminated."

So, I know the problem is in my mapping files. There is a 1 - 1 relationship between the ProviderTitle and ProviderTitleDetail tables. The ProviderTitleDetail is the sub-table of the ProviderTitle, and cannot exist without a ProviderTitle. A ProviderTitle may or may not have a ProviderTitleDetail.

Suggestions on mapping? Heck, even a pointer towards a section of documentation that cover this would be helpful. I'm not sure why NHibernate is not persisting the object correctly. If I debug the objects before I call Flush(), their IDs are set correctly.

Thanks.
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wolli · **Posted:** Thu Feb 05, 2009 4:10 am

I think you need to put constrained="true" to the other end of the association.