The Windows Azure Table Service supports optimistic concurrency for entity updates. Each entity has an associated entity tag (ETag) that changes whenever the entity is updated. A storage operation that updates or deletes an entity will succeed only if it provides either the current ETag or the special ETag value of "*", which forces the change to be accepted by the Windows Azure Table service.
A context, either TableServiceContext or DataServiceContext, keeps a list of the entities it is currently tracking. This list includes objects added to the context with TableServiceContext.AddObject() or attached through TableServiceContext.AttachTo(). Unless configured otherwise, the entities returned by a query are also tracked. Any modification to a tracked entity is submitted as the appropriate storage operation to the Table service when DataServiceContext.SaveChanges() or TableServiceContext.SaveChangesWithRetries() is invoked.
The TableServiceContext...