SQL
SQL was initially developed at IBM by Donald D. Chamberlin and Raymond F. Boyce after learning about the relational model from Ted Codd in the early 1970s. This version, initially called "SEQUEL" ("Structured English Query Language"), was designed to manipulate and retrieve data stored in IBM's original quasi-relational database management system, System R, which a group at IBM San Jose Research Laboratory had developed during the 1970s.
XDB Enterprise Server
XDB Enterprise Server is a relational database management system (DBMS), which was available for DOS, Windows NT and OS/2, and was compatible with IBM's DB2 database. DOS version was released in 1988 as one of the earliest DOS-based SQL database servers. The system was developed by XDB Systems, Inc., which was acquired by Micro Focus International group in 1998. It is still shipped with Micro Focus' COBOL software.