Why does NHibernate not realise my domain object needs updating, not inserting?

Question

Hi all

I have a web page which uses NHibernate to load a domain object. The object's state is then stored in the page controls, and when the user clicks the save button, a new object is created and its properties (included the Id) are populated from the page controls. I then call session.Save() on the object.

This to me means that NHibernate should use an UPDATE rather than an INSERT, because the Id property has been set and differs from the unssaved-value. However, NHibernate is attempting to insert it.

I have included the part of the mapping file relating to the Id below:

<id name="Id" column="StoredWillId" unsaved-value="0">
  <generator class="native" />
</id>

Can anyone explain what's going on here?

Thanks

David

Answer 1

Call session.SaveOrUpdate(). session.Save() inserts, session.Update() updates, session.SaveOrUpdate() saves if Id is 0, otherwise updates.