SQL Azure offers the scale and functionality of an enterprise data center without the administrative overheads that are associated with on-premise instances of SQL Server. This self-managing capability enables organizations to provision data services for applications throughout the enterprise without adding to the support burden of the central IT department or distracting technology-savvy employees from their core tasks in order to maintain a departmental database application.

With SQL Azure, you can provision your data storage in minutes. This reduces the initial costs of data services by enabling you to provision only what you need. When your needs change, you can easily extend your cloud-based data storage to meet those needs.

SQL Azure is built on proven Windows Server and SQL Server technologies, and is flexible enough to cope with any variations in usage and load. The service replicates multiple redundant copies of your data to multiple physical servers to maintain data availability and business continuity. In the case of a hardware failure, SQL Azure provides automatic failover to optimize availability for your application.

A key advantage of SQL Azure is the ease with which you can scale your solution. After partitioning your data, the service scales as your data grows. A pay-as-you-grow pricing model makes sure that you only pay for the storage that you use, so that you can also scale down the service when you do not need it.

When developers create on-premise applications that use SQL Server, they use client libraries that use the tabular data stream (TDS) protocol to communicate between client and server. SQL Azure provides the same TDS interface as SQL Server so that you can use the same tools and libraries to build client applications for data that is stored in SQL Azure. For more about TDS, see Network Protocols and TDS Endpoints.

SQL Azure will seem very familiar to developers and administrators because data is stored in SQL Azure just like it is stored in SQL Server, by using Transact-SQL. Conceptually similar to an on-premise instance of SQL Server, a SQL Azure server is logical group of databases that acts as an authorization boundary.

Within each SQL Azure server, you can create multiple databases that have tables, views, stored procedures, indices, and other familiar database objects. This data model makes good use of your existing relational database design and Transact-SQL programming skills, and simplifies the process of migrating existing on-premise database applications to SQL Azure. For more about Transact-SQL and its relationship to SQL Azure, see Transact-SQL Support (SQL Azure Database).

SQL Azure servers and databases are virtual objects that do not correspond to physical servers and databases. By insulating you from the physical implementation, SQL Azure enables you to spend time on your database design.