Stand-alone data manipulation programs

GP is a Data Manipulation Language (DML) used in connection with TASKMASTER, a Data Base Management System (DBMS) developed specifically to facilitate Engineering design. Experience with GP is described, and a number of inferences made. In particular, a case is made for the consistent use of stand-alone Data Manipulation Programs (DMPs), which interface between the Data Base and independently-developed external application programs. A DMP would be written in the DML associated with a specific DBMS, and it would in general be of one of two types: either a preprocessor, which extracts selected data from the Data Base and formats it as input to the external program, or a postprocessor, which stores selected output of the external program in the Data Base. DMPs should be operable either in Interpret or Compile mode and should include powerful facilities for User intervention at run-time. The DML should contain a LOOP facility, similar in form and use to, but rather different in concept from, the common DO/PERFORM feature.