Source : Free On-Line Dictionary of Computing

database manager
     
        The part of the database management system (DBMS) that handles
        the organisation, storage and retrieval of the data.  A
        database manager may work with traditional programming
        languages, such as COBOL and BASIC, or may work only with its
        proprietary programming language.  The terms database manager
        and database management system are used interchangeably.
     
        A database manager links two or more files together and is the
        foundation for developing routine business systems.  Contrast
        with file manager, which works with only one file at a time
        and is typically used interactively on a personal computer for
        managing personal, independent files, such as name and address
        lists.