Nhibernate updating version column on foreign key entity

Question

I am using c# with Fluent NHibernate and auto mapping.

Here is some code (truncated for clarity), then I'll explain the problem.

public class Company
{
    public virtual string Description { get; set; }
}
public class Stock 
{
    public virtual Product Product { get; set; }
    public virtual Company Company { get; set; }
}

Mapping

mappings.Conventions.Add<CascadeConvention>()
    .Conventions.Add<CustomForeignKeyConvention>()
    .Conventions.Add<HasManyConvention>()
    .Conventions.Add<VersionConvention>()

• CascadeConvention just sets everything to All.
• CustomForeignKeyConvention removes the _id that NHibernate usually appends to foreign key id columns.
• HasManyConvention sets all HasMany's to inverse.

• VersionConvention convertion looks like this:

  instance.Column("Version");

  instance.Default(1);

The problem is that when I insert a new stock record, Nhibernate also updates the version number on the related Company. If I had an IList<Stock> property on the Company then that would make sense but I don't.

I've done a lot of reading around:

• NHibernate emitting extraneous update statements regardless of proper Inverse (fluent nhibernate) settings on relations
• Cascade Save-Update in NHibernate and version column
• NHibernate Reference - Chapter 17. Example: Parent/Child
• Ayende @ Rahien - NHibernate Mapping

From these, I've tried a whole bunch of things including adding .Not.OptimisticLock() all over the place. I even added an IList<Stock> property on Company so that I could specifically set it as Inverse, Not.OptimisticLock, etc. Nothing I do seems to make any difference.

Answer 1

We eventually sorted this by moving to a Session-per-request paradigm. Not sure why it was going wrong or why this fixed it. I wrote numerous unit tests to try and reproduce the behaviour in a more controlled environment without success.

In any case, it works now. There are good reasons session-per-request is often given as the best practice way to manage NHibernate sessions in a web application.