Sybase SQL Server was one of the early client-server relational database systems, built around Sybase’s DataServer product in the late 1980s. It is most often remembered for its role in the origins of Microsoft SQL Server. A history written by a member of the SQL Server team and preserved in Microsoft’s documentation archive records that “in 1987 Microsoft and Sybase started a partnership to build/sell a Database Management System, based on the then (yet to be released) Sybase DataServer product,” with Sybase holding the rights on the Unix and minicomputer platforms and Microsoft holding the rights on OS/2 and Microsoft’s own operating systems.
Under that arrangement the OS/2 port of Sybase DataServer was announced as Ashton-Tate/Microsoft SQL Server, while, as the same account notes, “Sybase later renamed their product to Sybase SQL Server for UNIX and VMS.” Microsoft’s own 1989 history timeline confirms the shipment of Microsoft SQL Server 1.0 on May 3, 1989, “the result of a joint development effort of Ashton-Tate, Microsoft, and Sybase.” For several years most of the engineering was done by Sybase, with Microsoft contributing testing and project management before gaining fuller access to the code.
The Microsoft account describes how the two companies diverged: Sybase wanted to remain platform neutral while Microsoft committed fully to Windows NT, and in 1994 the partnership was dissolved so that Sybase could sell its own product on OS/2 and Windows and Microsoft could take the code in its own direction. Sybase’s database, later renamed Adaptive Server Enterprise, continued as an independent commercial product, and the company was eventually acquired by the enterprise software firm SAP.
Note on dates: this entry uses a year-level date of 1987 for the start of the Microsoft-Sybase partnership, as recorded in Microsoft’s own history of SQL Server, rather than asserting a specific founding day for the product.