Session.CreateSqlQuery忽略Session.Update之后的更新值

Question

Problem

I have a Session.Update() updating the status of a row. The next line of code is a Session.CreateSqlQuery() with a more complex update query. They are both inside a transaction, as follows:

private void RemoveReferences(Person obj)
{
    //Session is ISession
    //Person contains multiple Activity, that can contains multiple DetailedActivity.

    using (var tx = Session.BeginTransaction())
    {
        foreach (var act in obj.Activities)
        {
            var det = Session.QueryOver<DetailedActivity>()
                .Where(w => w.Activity.CdActivity == act.CdActivity)
                .Take(1).SingleOrDefault();

            //Null validation removed...

            det.Date = null;
            det.Activity.Stage = 2; //Example of value being updated.
            Session.Update(det.Activity);
            Session.Update(det);
         }

         Session.Flush();

         //More code removed...

         //The next code is blind to any updated value from the code above.
         //For example, the value Stage still keeps its old value 
         //if I try to get if from a CreateSqlQuery.

         //Tries to remove the Person reference from the Activity.
         Session.CreateSQLQuery("Update activity ac " +
                                "Set cd_person = null " +
                                "From det_activity da " +
                                "Where ac.cd_activity = da.cd_activity " +
                                "And ac.cd_person = :cdPerson " +
                                "And Coalesce(ac.stage, 1) = 2 " +
                                "And da.Date is null;")
        .SetParameter("cdPerson", obj.CdPerson).ExecuteUpdate();

        tx.Commit();

        //Try/catch removed for brevity;
    }

This code is a simplified version of what I'm really working with, but the two basic blocks of code are there.

For a CreateSqlQuery call, the value updated by a previous Session.Update() is not being "seen". I tried to get that row of activity using the CreateSqlQuery and it still returns the old value.

Questions

Why is the CreateSqlQuery not seeing the updated value?

Is there any way to make the CreateSqlQuery see the updated value?

Answer 1

If I read that correctly, you seem to have misunderstood what "Update()" does. You may want to refer to the reference documentation: http://nhibernate.info/doc/nhibernate-reference/manipulatingdata.html#manipulatingdata-updating

When you are working with an instance that you just loaded and want to update it inside the same session , as you seem to be doing here, it's enough to just modify the object. The change will be sent to the database during NHibernate's dirty check and flush stage.

Save(), Update() and SaveOrUpdate() are used for new objects, or for objects loaded in a previous session that you wish to attach to a new session. They tell the NHibernate session to "please register this object for a later dirty check" (during some scenarios Save() may trigger immediate INSERT for technical reasons but that is a side-effect and not a promise).

However, Update() should do no harm (it should be a no-op), and you do also call Flush() explicitly which should transmit your modifications to the database.

So the explanation must lie elsewhere...

What exactly is Session in this code? Are you sure it's the exact same session instance throughout?

How are the classes mapped? Anything with regards to flush rules, read-only properties etc?