SQL Server 2005 is the latest version of a database server product that has been evolving since the late 1980s. Microsoft SQL Server originated as Sybase SQL Server in 1987. In 1988, Microsoft, Sybase, and Aston-Tate ported the product to OS/2. Later, Aston-Tate dropped out of the SQL Server development picture, and Microsoft and Sybase signed a co-development agreement to port SQL Server to Windows NT. The co-development effort cumulated in the release of SQL Server 4.0 for Windows NT. After the 4.0 release, Microsoft and Sybase split on the development of SQL Server; Microsoft continued forward with future releases targeted for the Windows NT platform while Sybase moved ahead with releases targeted for the UNIX platform, which they still market today. SQL Server 6.0 was the first release of SQL Server that was developed entirely by Microsoft. In 1996, Microsoft updated SQL Server with the 6.5 release. After a two-year development cycle, Microsoft released the vastly updated SQL Server 7.0 release in 1998. SQL Server 7.0 embodied many radical changes in the underlying storage and database engine technology used in SQL Server. SQL Server 2000, the accumulation of another two-year development effort, was released in September of 2000. The move from SQL Server 7.0 to SQL Server 2000 was more of an evolutionary move that didn’t entail the same kinds of massive changes that were made in the move from 6.5 to 7.0. Instead, SQL Server 2000 built incrementally on the new code base that was established in the 7.0 release. Starting with SQL Server 2000, Microsoft began releasing updates to the basic release of SQL Server in the following year starting with XML for SQL Server Web Release 1, which added several XML features including the ability to receive a result set as an XML document. The next year they renamed the web release to the more succinctly titled SQLXML 2.0, which, among other things, added the ability to update the SQL Server database using XML updategrams. This was quickly followed by the SQLXML 3.0 web release, which included the ability to expose stored procedures as web services. Two years later, Microsoft SQL Server release history cumulates with the release of SQL Server 2005. SQL Server 2005 uses the same basic architecture that was established with SQL Server 7 and it adds to this all the features introduced with SQL Server 2000 and its web releases in conjunction with the integration of the .NET CLR and an array of powerful new BI functions. The following timeline summarizes the development history of SQL Server:

- 1987 Sybase releases SQL Server for UNIX.

- 1988 Microsoft, Sybase, and Aston-Tate port SQL Server to OS/2.

- 1989 Microsoft, Sybase, and Aston-Tate release SQL Server 1.0 for OS/2.

- 1990 SQL Server 1.1 is released with support for Windows 3.0 clients.

- Aston-Tate drops out of SQL Server development.

- 1991 Microsoft and IBM end joint development of OS/2.

- 1992 Microsoft SQL Server 4.2 for 16-bit OS/2 1.3 is released.

- 1992 Microsoft and Sybase port SQL Server to Windows NT.

- 1993 Windows NT 3.1 is released.

- 1993 Microsoft and Sybase release version 4.2 of SQL Server for Windows NT.

- 1994 Microsoft and Sybase co-development of SQL Server of. cially ends.

- Microsoft continues to develop the Windows version of SQL Server.

- Sybase continues to develop the UNIX version of SQL Server.

- 1995 Microsoft releases version 6.0 of SQL Server.

- 1996 Microsoft releases version 6.5 of SQL Server.

- 1998 Microsoft releases version 7.0 of SQL Server.

- 2000 Microsoft releases SQL Server 2000.

- 2001 Microsoft releases XML for SQL Server Web Release 1 (download).

- 2002 Microsoft releases SQLXML 2.0 (renamed from XML for SQL Server).

- 2002 Microsoft releases SQLXML 3.0.

- 2005 Microsoft releases SQL Server 2005 on November 7th, 2005.