DATATRIEVE is a database query and report writer tool from Hewlett-Packard. It runs on the OpenVMS operating system, as well as several PDP-11 operating systems. DATATRIEVE's command structure is nearly plain English, and it is an early example of a Fourth Generation Language (4GL). It works against flat files, indexed files, and databases. Such data files are delimited using record definitions stored in the Common Data Dictionary (CDD), or in RMS files.