c# DataContext.SubmitChanges() not updating database

Can someone explain why the following code fails to update the database or what else I can do to troubleshoot?

// *********************************
// People Updates
// *********************************
// In Engr and SoE
EmplIDs = InputList.GetPeopleIds(InputType.Engr | InputType.SoE);       // retrieve IDs in tables Engr and SoE
Engr = DB.GetEngrByIds(EmplIDs);                                        // retrieve objects from Engr
SoE = DB.GetSoEByIds(EmplIDs);                                          // retrieve objects from SoE
Batch.Update开发者_如何学运维(SoE, Engr);                                                // update SoE with Engr data
DB.Save(SoE);                                                           // persist


// Inside DB repository
public void Save(List<SoE_People> people) {
    ChangeSet cs = dc.GetChangeSet();
    foreach (SoE_People person in people.Where(p => cs.Updates.Contains(p))) {
        person.LastUpdate = DateTime.Now;
    }

    dc.SubmitChanges();
}

I've checked the following:

• people.Count ~ 2500, cs.Updates.Count ~ 200
• dc.GetChangeSet.Updates.Count = 0 after calling SubmitChanges()
• all updates to the people object are correct. They are visible in the locals window via people and cs.Updates[x]
• no exceptions are thrown by dc.SubmitChanges()
• setting dc.Log = Console.Out shows no SQL for the SubmitChanges()
• a previous section of the code that inserts new records via dc.InsertAllOnSubmit() works fine -> no write permission problem.
• manually cutting and pasting data into the SoE_People table works -> no foreign key constraint problem.

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Without even looking into the logic you have above, here are some recommendations:

• Put everything in a try/catch. How do you know there's no exception being thrown?
• dc.SaveChanges() returns an int - number of records that were CRUDed. Capture the return value and check it.

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I'm not familiar with DataContext (don't use it), but I'll throw this out there.

If it's like an SqlDataAdapter, did you write/define the SQL text for inserting or updating your records?

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You have probably overridden SoE_People update in the datacontext. There should be a this .ExecuteDynamicUpdate(instance).

Look there maybe you have commented / removed that.

You can take a look here if you don't understand what I mean: Custom Entity Insert/Update/Delete Method Validation.

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Maybe it is not the code, it is the database table. I had the issue to update the table use that SubmitChanges(). I fixed the problem by giving the table a primary key.