Azure Mobile Service concurrency handling in SQL?

Question

I am implementing an Azure Mobile Service and I have a set of objects that can be accessed by multiple users, potentially at the same time. My problem is that I can't really find a lot of information on how to handle the potential concurrency issues that might result from this.

I know "Azure Tables" implements an E-Tag check. Is there an out-of-the-box solution for Azure Mobile Services for this one with SQL ? If not, what is the approach I should be going for here.

Should I just implement the E-Tag check by hand? I could include a GUID of the object that is generated every time the object is saved and checked when saving. This should be relatively safe way to do it?

Answer 1

For conflicts between multiple clients, you would need to add a detection/resolution mechanism. You could use a "timestamp" (typically a sequentially incremented version number) in your table schema and check it in your update script. You could fail an update if the timestamp used by a client for reading is older than the current timestamp.

If you want to use ETags via http headers, you could use Custom APIs. We are looking into enabling CRUD scripts to also set headers but that is not available today. Separately, we are looking into the offline scenarios as well.

(Prog Manager, Windows Azure Mobile Services)