At the Microsoft 2009 Professional Developer Conference (PDC) Sheila Molnar and I sat down with Dave Campbell, Microsoft Technical Fellow, to discuss the significance of SQL Azure and Microsoft’s “Dallas” project. Dave told us that Microsoft’s goal for SQL Azure is to make it the premier data source for Windows Azure applications. While there’s no doubt that SQL Azure’s nature as a global database will appeal to a certain class of application developer, he felt that the real magic will be found in the joining of on-premises and cloud-based applications in ways that aren’t possible with traditional on-premises applications.

Dave noted that “the magic is we’ve separated physical and logical administration. The whole notion of managing the iron we want to take away. You don’t have to worry about where the transaction log disc is, for example. The logical administration: You get to define the relational schema. You get to define your indexes. That’s what the business of running applications is about. We want to give you as much of the top and take away as much of the bottom as we can.”

One of the benefits of joining traditional database iron with the SQL Azure cloud for on-premises business is the ability to quickly surge database capability to meet changing demands. A highly scalable, globally accessible database can be provisioned in seconds—making it easy to adapt to variable business demands such as sales campaigns or creating data hubs that collect data from multiple branches or distributed business. Dave felt that SQL Azure opened up a completely new class of applications that could provide business with capabilities that they never had before.

Dave saw the role of the traditional DBA evolving as companies embrace SQL Azure projects. DBAs involved with SQL Azure won’t have to worry about basic server management issues like performance tuning, backup, and scalability. Instead, they will be able to focus on database design and data access issues potentially making them more important to the organization.

Dave noted that some customers initially had concerns about using the Tabular Data Stream (TDS) protocol to connect to SQL Azure because they felt that TDS could be susceptible to latency issues. However, he explained that TDS actually is quite tolerant of latencies having been designed with the capability of dealing with variable results from a number of commands like multiple result sets or even cursors. Additionally, when used as a database for Windows Azure applications, for all intents and purposes SQL Azure essentially is an on-premises database for Windows Azure applications with few latency issues.

When asked about how customers felt about the security of SQL Azure applications Dave stated that he felt that trust in cloud security would grow over time. He pointed out the number of business that have adopted outsourced payroll with virtually no security concerns despite the highly confidential data contained in a payroll. In the same way, as businesses become more familiar with SQL Azure and other cloud based services they will find the security concerns to be acceptable.

Dave also told us about Microsoft’s new Dallas product, which is designed to deliver very targeted public data to developers and information workers as a service. Dallas holds public data from the Associated Press, Citysearch, DATA.gov, NASA, Weather Central, National Geographic TOPO! and other public data sources in SQL Azure. Dave thought Dallas could be a game-changing technology by liberating the data that you know is out there and helping you to find it. At the time of this writing Dallas is currently an invitation-only community technical preview (CTP).

There’s no doubt that Microsoft takes the cloud very seriously, but it’s also clear that the company doesn’t expect existing SQL Server systems to go away anytime soon. Quite the contrary, they view the cloud as way of extending your existing SQL server iron to the cloud enabling a new class of applications that can do more than just standalone SQL Server systems. The idea behind SQL Azure isn’t to displace existing SQL Server systems but rather to extend them in ways that weren’t possible before.

SQL Azure has been generally available since January of 2010. You can read about some of my early experiences using SQL Azure in “Getting started with SQL Azure Database,” Instant Doc ID 103133. You can find out more about SQL Azure at the Microsoft SQL Azure site.