Microsoft

Originally started SQL Server with Sybase

Microsoft SQL Server is a relational database management system developed by Microsoft. As a database server, it is a software product with the primary function of storing and retrieving data as requested by other software applications—which may run either on the same computer or on another computer across a network (including the Internet).
 * https://en.wikipedia.org/wiki/Microsoft_SQL_Server


 * http://www.microsoft.com/sqlserver
 * http://technet.microsoft.com/en-us/sqlserver/default