Many to one mapping problem with NHibernate

Question

Firstly I am relatively new to NHibernate. Got two tables on TaxMapping and Address. A single TaxMapping must have one address and one address can belong to more than one Tax Mapping. They are linked through foreign key

TaxMapping hbm

<?xml version="1.0" encoding="utf-8" ?>
<hibernate-mapping xmlns="urn:nhibernate-mapping-2.2" namespace="ITAPDTO" assembly="ITAPDTO">
<class name="TaxMapping" table="tblTaxMapping">
<id name="Tax_Mapping_ID">
  <column name="Tax_Mapping_ID" sql-type="bigint" not-null="true"/>
  <generator class="identity" />
</id>
<property name="Tax_ID" />
<property name="Client_Code" />
<property name="NRA_Sub_Account" />
<property column="Domicile" type="String" name="Domicile" length="5" />    
<many-to-one name="Address"   column="AddressID" cascade="none" not-found="exception"  not-null="true"  fetch="join"    class="ITAPDTO.Address,ITAPDTO" />
</class>
</hibernate-mapping>




<?xml version="1.0" encoding="utf-8" ?>
<hibernate-mapping xmlns="urn:nhibernate-mapping-2.2" namespace="ITAPDTO" assembly="ITAPDTO">

<class name="Address" table="Address">
<id name="AddressID" column="AddressID" type="Int32" unsaved-value="0">
  <generator class="identity"/>
</id>
<property column="Client" type="String" name="Client" not-null="true" length="100" />
<property column="Contact" type="String" name="Contact" not-null="true" length="50" />
<property column="Address1" type="String" name="Address1" not-null="true" length="100" />
<property column="Address2" type="String" name="Address2" not-null="true" length="100" />
<property column="Address3" type="String" name="Address3" not-null="true" length="100" />
<property column="City" type="String" name="City" not-null="true" length="50" />
<property column="State" type="String" name="State" not-null="true" length="50" />
<property column="PoBox" type="String" name="PoBox" not-null="true" length="50" />
<property column="PostCode" type="String" name="PostCode" not-null="true" length="20" />
<property column="Country" type="String" name="Country" not-null="true" length="50" />
<property column="InsertedBy" type="String" name="Modified_By" length="20" />
<property column="InsertedOn" type="DateTime" name="Modified_Date" />
<property column="ConfirmedBy" type="String" name="Approved_By" length="20" />
<property column="ConfirmedOn" type="DateTime" name="Approved_Date" />
<property column="Status" type="String" name="Status" />
<property column="IUD" type="String" name="IUD" />
</class>
</hibernate-mapping>

I can pull in the data and bind to grid view with no issue. However when I update the Taxmapping the AddressID for the Address oject is always null event thoughh the other address fields are correctly populated and I dont know why. I currently have a hack in place the pulls the id from the db before I call update but I really shouldn't have to do this. Any thoughts would be welcome regards

Answer 1

Is this due to cascade being set to "none" on the Taxmapping object's Address property? Try changing it to "save-update". You may also want to read the nhibernate documentation to figure out which cascade setting would be best for your situation, though it sounds like "save-update" would be most appropriate.

Answer 2

In addition to Krazzy's point, you should also check that your sessions are closed and / or flushed appropriately. A long-running session which is never flushed can exhibit similar problems.