SDS is a part of Azure platform. Azure platform offers the following services: Windows Azure (Operating System in cloud), Microsoft .NET Services (set of WCF based services), SQL Azure (relational database in cloud)
This service provides SQL server capabilities in cloud. We can create a database which is currently in the CTP (Community Technology Preview) form. We can have all the benefits of working with SQL Server plus no hazards of doing the administration. Thus administration tasks like replication, availability will be automatically made available to us. There will be 3 copies of data maintained out of which 2 will be synchronized and the third one may lag a bit. This also leads to limiting the size of the database to 10 GB. The size limitation is for 2 reasons, one for availability (in order to replicate the data in cloud, it needs to be within limit) and the second being shared database box for multiple users (as the same box will be used for storing the data from many users. If the size of data is huge for a single user, then the box will not be scalable to other users hence limit in size)
When we are maintaining data in the cloud again, we have 2 options of creating applications. One in which data is near the code, which means we have application running on the same box where we have data. Another will be where data is far from the code, in which we will be always manipulating data from the cloud (in case of web based application client).
How is the service provided?
The service is made available with the help of TDS (Tabular Data Stream) protocol. There are accounts available for billing purpose which will own one or more servers as per requirement. Each server will have one or more databases. These servers will use SQL Server authentication model. The databases will have one or more SQL users with respective permissions. Thus maintaining logical administration in the form of the creating views, creating triggers, tuning queries, tuning indexes etc. will be the job requirement of DBA rather than physical management in the form of how many file groups will be required, taking backup, recovery etc.
As of now, functionality like service broker, CLR (Common Language Runtime) functionality is not available with SDS, but will be subsequently made available.
How can SDS be used?
There can be various scenarios in which this service can be used.
- In small organizations, IT groups for maintaining relational database may not be available.
- In big organizations, if there is an inter department requirement for maintaining another copy of relational database, proving IT support becomes very difficult as IT staff is already overburdened.
- For creating web applications in which maintaining SQL Server for the web application may be very costly.
How can I start using SQL Azure?
You will have to register for using the current CTP over here http://msdn.microsoft.com/en-us/sqlserver/dataservices/default.aspx
You will receive the invitation for using SQL Azure which can be used with your Windows Live ID.