1. A computerized method for retrieving data from a database stored in a data storage device of a data processing system having a central processing unit (CPU), memory, an operating system and a database management system (DBMS), using an application program written in an interpretive programming language, comprising the steps. of: (a) initializing by means of the CPU implementing a set of commands, a data processing environment for processing the application program; (b) executing the application program using a Rexx program interpreter stored in the data processing system memory; and (c) processing mapping call instructions for mapping constructs of the DBMS to constructs of the programming language, operating system call instructions, and DBMS call instructions for extracting data from the database, contained in the application program.