The code base for the MS SQL server of version 7 was initially sold by the original company Sybase sql server to the software giant of the cyber space Microsoft. It was the first entry of the Microsoft Company to the database market at the enterprise level. The objective was to compete against the other companies like the IBM and the ORACLE. It was actually Microsoft, Sybase and the astob Tate that originally formed a team to create and launch the very first version of the SQL server 1.0 for the OS /2. It happened during the year 1989. It was just the same as the Sybase SQL server 3.0 on the UNIX platform and the VMS etc.
There was a Drift in the History of SQL Server later on by around 1992 when Microsoft SQL server version number 4.21 was also shipped around. Around 1993, the companies parted away as the Windows NT was released. Yes, Sybase and Microsoft got separated. Own design and the marketing schemes are sketched out. Microsoft started to negotiate the exclusive rights for all the versions that belonged to the SQL server and written for the operating systems.
Adaptive server enterprise was the new name for the Sybase by around 1996. It is done to avoid the confusion in the minds of the users to distinguish clearly between the Microsoft SQL server and their own product. By around 2005, the legacy code for the Sybase SQL server was completely rewritten.
Likewise, in that way the History of SQL Server dates back to very long time. It could really be interesting for the modern day technical geeks and professionals to infer these facts closely. Identifying the transitions that had taken place earlier with the prominent conglomerates in the field of information technology, could unleash a lot of mysteries.