Microsoft will only support SQL Server 2005 running Service Pack 2 on Vista and Longhorn.

The company have suggested that customers running SQL Server 2000 and earlier versions, such as 7.0 and 6.5, should move to its newest release, SQL Server 2005.

Service Pack 2 (SP2) has not yet been released but should appear early next year. The free version of the database, SQL Server 2005 Express Edition, formerly called Microsoft Database Engine (MSDE), will also not be supported by Windows Vista and Longhorn.

Older versions of SQL Server could potentially work on Vista and Longhorn, but Microsoft isn't testing them, said Matthew Stephen, a data platform technical solution professional who works for Microsoft in the UK. By the time Longhorn server comes out - scheduled for the second half of 2007 - SP2 should be well-tested, he said.

Microsoft positioned the decision as a way to provide users with better security, saying SQL Server 2005 is designed to take advantage of better security and performance features in the upcoming operating systems.

The move may also be designed to wean people off the older database release, which would be expected since SQL Server 2000 is aging, said David Cartwright, a freelance software developer and database tester in the UK "There's going to be a concerted push to get people on [SQL Server] 2005," he said.

SP2 will likely tap into enhancements to Microsoft's .Net development platform as well as in the new OSes, which older versions of the database won't be able to do, Cartwright said. Service packs usually also contain bug fixes.

Mainstream support for versions of SQL Server 2000, including the developer, enterprise and standard editions, is due to end in August 2008. The products will then go into extended support for another five years, according to Microsoft's Web site.

The issue shouldn't be too much of a burden for users. Although Windows Vista is due to debut later this month for business customers, most will wait at least nine months to a year before adopting it, Cartwright said.