Enter Data Services

When it comes to building distributed applications, your mileage will vary with the array of data access technologies. Dealing with serialization and concurrency issues in those environments is beyond the scope of this article. However, it is important to mention what appears to be yet another data access technology available from Microsoft called ADO.NET Data Services, formerly code-named
“Astoria”. Astoria was made available with .NET 3.5 SP1.Astoria is an HTTP service layer built on top of WCF that provides a REST-style
API to your data, giving each of your elements of data a unique URI (for example, http://host/northwind.svc/Products(1) ). Out of the box, this service can be enabled for an Entity Framework model or any other IUpdateable/IQueryable data source in just a few lines of code. Data is queryable and updateable via pure
HTTP verbs (PUT, POST, DELETE, and GET) using query strings and HTTP payload. Data can be serialized in either AtomPub or JSON format. The net effect is that your data model is widely interoperable with a dizzying array of potential clients and technologies.
Although you are free to build up complex query strings and HTTP payloads for just about any type of operation, the Astoria team has created client libraries to assist in these endeavors. Firstly, an ASP.NET Ajax library is available on
CodePlex to allow JavaScript developers to easily work with Astoria Services.
Secondly, as part of the core installation, there is a .NET Client Library which provides a natural query model using LINQ and projecting data into client side
.NET objects for use by your .NET or Silverlight projects.
A new project, currently named “RIA Services” (code-named “Alexandria”), builds on top of ADO.NET Data Services by also providing rich validation and UI cues on top of your data model in a client/server model. This technology probably won’t be released until around the .NET 4.0 timeframe, but it is definitely something you should keep your eye on.