[This article was contributed by the SQL Azure team.]

Today we announced the details of our plans to accelerate the delivery of core relational database features as part of SDS.  There has been quite a bit of buzz about SDS over the past couple weeks and it is great to be able to share the details more broadly.

If we flash back about a year ago to Mix 08, Nigel Ellis got up on stage to introduce the community to SDS which, at the time, was a flexible entity based cloud database that you accessed using standard internet protocols. We made this announcement with the promise that more relational capabilities would be coming – and they did. But the universal feedback we received from our TAP partners and other early adopters was the need for a relational database delivered as a service. This was extremely valuable feedback and drove us to more aggressively investigate ways in which we could deliver these features. As a result of that work and based on the progress we’ve since made in the product team, we are announcing that SDS will deliver full relational database capabilities as a service.

While we knew we needed to accelerate our plans we also knew we needed to hold true to some on the founding principles we had when we started our journey. Things like High Availability, Fault Tolerance, Friction Free Provisioning, Pay As You Grow Scaling, Immediate Consistency. We are still delivering on these promises and have added to the mix true relational capabilities, T-SQL and compatibility with the existing developer and management tools ecosystem.

What does this mean for developers? Developers will be able to very easily provision themselves a logical server and database and begin developing against it immediately using the existing tools and technologies that they are accustomed to. We are providing an experience where a developer can take an existing application and just change the connection string to point it to the cloud and have it just work.

How will we do it? Three letters TDS. TDS stands for Tabular Data Stream and it’s the published protocol that clients use to communicate with SQL Server. From its inception, SDS has always been built on the SQL Server technology foundation and it just made sense to allow our users to access their data via TDS. Most importantly for developers, this means symmetric SQL Server functionality and behavior combined with compatibility with the existing tools you are familiar with.


                Stored Procedures?…Check




                Visual Studio Compatibility?…Check

                ADO.Net Compatibility?…Check

                ODBC Compatibility?…Check

To be clear, the above is not a complete list of supported features.  However, given the feature set we are planning to support in SDS v1, a majority of database applications will “just work”, allowing developers to target on and off-premises deployments with essentially the same code base.  The initial scenarios we are targeting are things like web and departmental applications. We will be posting some content to our MSDN Dev Center in the coming weeks with specifics and getting started guidance but I encourage everyone to download SQL Express and the Windows Azure SDK to get started.

The core foundational components of SDS have not changed. This is still the same architecture that we have been telling you about for the past year and that underlies the current CTP bits. It is the same architecture that is powering some of Microsoft’s key service properties and in the next few months will be used to store 100’s of terabytes of data in production deployments. Our early adopters (both internal and external) have shaken it down pretty well and we feel very confident about these bits.  The only difference is we are now providing a rich SQL model while maintaining the high availability, fault tolerant and scale aspects of the system.

What about the ACE (Authority, Container, Entity) data model and developer experience? Since Windows Azure storage has a similar data model (property bag) and developer experience, we will stop supporting the current ACE Model sometime in the future. Does this mean you can’t access your relational data via internet friendly protocols like REST?  Not at all. You can still access your relational data (located on premises or in the cloud) via HTTP/REST using the ADO.Net Data Services framework. The compatibility with existing tools and technologies is a really important point to drive home and a super important value add that Microsoft provides.

Breadth and OSS developer support will continue to be a high priority for us and we will continue to support and provide breadth development libraries for all mainstream development technologies including PHP, Ruby and Java.  If it works with SQL Server, it will largely work with SQL Data Services.

What about Security? All communications with our service is SSL encrypted and our initial authentication will be using SQL Authentication.

Of course, SQL Data Services remains one of the key developer services of the Azure Services Platform – that hasn’t changed. Consuming SDS from within an Azure application has never been easier and we will continue to ensure this is a feature rich, friction-free experience.

I have said a lot, so go ahead and digest all of this. What else do you want to know? As I am sure you all have more questions, feel free to email me at and I’ll post the questions and answers for all to see.

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