The company said the update to its relational database will offer performance enhancements and support 64-bit computing.
The new release will allow users to embed .net code directly in a database, but this means potentially being locked into the Windows platform, analysts said.
Existing relational databases use the Ansi-standard structured query language (SQL), but with SQL Server 2005 Microsoft has added support for .net and Soap.
Tim Sneath, architectural engineer at Microsoft, said programming with .net within SQL Server could solve problems such as e-mail validation.
Soap could be used to access a database from a non-Microsoft platform without proprietary middleware, said Mark Quirk, head of technology, .net and developer group at Microsoft.
"Unix and Linux [users] would be able to access SQL Server as long as the [platform] supported web services," he said.
Using .net as the interface may solve some problems, but it is a departure from the way SQL Server databases are built, where embedded code is written in SQL.
Mike Thompson, principal research analyst at Butler Group, said .net provides a faster route into the database but that programmers would find it difficult to migrate applications to other relational databases.