Use of bipartite graphs as a notation for data bases

Studies on computing systems making use of data bases have produced various notations to represent `schemata' of relations between data. These notations use graphs both as a tool to describe features relevant to applications and as an effective method of teaching. However, a critical limit may be the fact that they handle in different ways the concepts relevant to data and those relevant to programs. As a matter of fact, the ways of handling concepts relevant to programs are often unsuitable. For example, note that an answer to easy requests may require fairly complex programs. This paper introduces a uniform notation both for data-base schemata and for a class of application programs. This is accomplished by associating a suitable interpretation with bipartite graphs