I have been using ADO.NET Data Service in Silverlight since Astoria team released the client library for Silverlight. I didn’t have a particular idea to use that service except this is something new that I like to try. After reading a few article about Astoria, I come to know that I can retrieve the data from Astoria service by typing the URL in browser. And we have to use the different HTTP verbs for CRUD operations. That’s all? I think “No”. So, I raised a question in MSDN forum last week. Today, I got very useful and informative reply from Mike Flasko. (Thanks a lot for your reply, Mike.)
Here is the original thread that I posted in MSDN forum. Now, I’m here to share this information with you all. Hope that you will find it useful.
Question : What is ADO.NET Data Service (Astoria)?
Could anyone please explain me about ADO.NET Data Service in plain english without using marketing term?
- we can query the data by typing URL in browser.
- it supports CRUD operations with different HTTP verb.
But I believe that there might be some important reasons why people created this framework.
- What is the ADO.NET Data Service?
- What are the advantages of using ADO.NET Data Service?
- What’s wrong with Web service?
- What is the reason why making differnt HTTP verb for CRUD operation?
Thanks in advance.
Answer from Mike Flasko (Astoria Program Manager [MSFT] )
- Creating and maintaining rich data oriented services with current approaches requires a significant developer investment
- Building generation purpose client libs/tools with current approaches to data centric services is hard
For #1, imagine you wanted to expose the data in your CRM database to you client tier application. Further assume you want to enable typical application scenarios like retrieving sorted views of the data, paging over the data, filtering, etc. To expose this data as a set of callable remote methods (using current approaches to developing web services) you would need to write a large number of methods to expose each of the entities in your CRM DB (customers, orders, etc) and then add additional methods for each to retrieve entities by key, sort them, page over them, etc etc. ADO.NET Data Services, addresses this issue by allowing you to declaratively state the contract of such a data centric service, by telling us the schema of the data and having the data services technology automatically create the required remote endpoints, enabling paging, sorting, etc with no code from the developer. Then as you change your data model, your service endpoints also change.
For #2 above, an interesting artifact of a REST-based approach to web services is that it promotes creating a uniform interface. That is, how you address items in an ADO.NET Data Service (i.e. how to construct URIs), how to interact with data (using HTTP verbs), etc is the same across any ADO.NET Data Service, regardless of the data it exposes. This uniform interface enables code reuse against your web services such that one can create reusable client libraries and UI widgets for all their services. For example, the ADO.NET Data Service team is doing this by shipping .NET , Silver light, AJAX, etc libraries which can talk to any data service. In addition, this feature (uniform interface) enables us to add features such as LINQ to ADO.NET Data Services since the translation of LINQ query statements to URIs is stable and well known.
This is already probably a bit too long Smile, but in addition to the items noted above, additional advantages of REST-based approaches also apply such as rich integration with HTTP such that you can leverage existing HTTP infrastructure (ex. HTTP Proxies) deployed at large …
I hope that helps….
Here are a few links for those who don’t know about REST Service.
Hope you find it useful.