Technical Reports (CIS)

Document Type

Technical Report

Date of this Version

December 1971


University of Pennsylvania Department of Computer and Information Science Technical Report No. MS-CIS-72-19.


The Data Description Language (DDL) is a language for describing the structure of data, and expressing transformations that are to be performed on that data. The DDL Processor is a set of computer programs which interprets DDL statements and generates a computer program to perform the specified transformations. Together the DDL and its Processor provide a utility which can be used to perform jobs such as creating new data bases, reorganizing or extracting data from existing data bases, moving data to different storage devices, interfacing files between different programming languages, or between different operating systems.

This report documents the design of the DDL Processor. Special features of the design include the use of special purpose internal languages, compiler-compiler techniques, bootstrapping methods, and a descriptor tree which aids in the parsing of input data.



Date Posted: 23 January 2008