Knecke

Looks like you are getting some entities with your select new EditableCallout, and those are not the entities you have in the database. If you want to insert or update you should do that on the entities that you have in the db and not on your "own" classes that is a combination of values from the database entities

He is doing that, he's getting a database entity then manually mapping data from a dto to that entity.

EditableCallout target = One(c => c.id == callout.id);
            if (target != null)
            {
                target.ProductIdentifier = callout.ProductIdentifier;
                target.DateEnd = callout.DateEnd;
                target.DateStart = callout.DateStart;
                target.Value = callout.Value;
                target.IsActive = callout.IsActive;
                wdc.SubmitChanges();
            }

@drdexter33 - Does your table have a primary key?