Relational data-base management and APL

Historically, the development of programming languages was driven by a desire to remove needless machine-oriented representation clutter from the programmer's purview. When compared with other implemented programming languages, APL goes quite far in this direction. However, like its competitors, APL provides almost no support for programs that have to access and possibly update data from shared data bases. Such data is usually subject to syntactic and semantic constraints that are declared on a community basis. Moreover, both the data and the constraints are subject to dynamic sharing with other independently-developed programs. We outline the principles underlying the relational model for formatted data bases, including the structures, algebraic operators, normalization, and formal data sublanguages. We conclude with a discussion of the need for a knowledge base (1) to act as a defining base for a proposed data base; (2) to mediate queries and transactions; and (3) to aid in query formulation in formal or natural language. A short list of references is given for those wishing more introductory information about relational database management.