SQL Server - Microsoft

Microsoft SQL Server is a relational database management system (RDBMS) produced by Microsoft. Its primary query language is Transact-SQL, an implementation of the ANSI/ISO standard Structured Query Language (SQL) used by both Microsoft and Sybase.

SQL Server is commonly used by businesses for small-to-medium-sized databases, but the past five years have seen greater adoption of the product for larger enterprise databases.

Their latest release is SQL Server 2005(version 9.0)