The Evolution of the Computerized Database

Abstract

Databases, collections of related data, are as old as the written word. A database can be anything from a homemaker's metal recipe file to a sophisticated data warehouse. Yet today, when we think of a database we invariably think of computerized data and their DBMSs (database management systems). How did we go from organizing our data in a simple metal filing box or cabinet to storing our data in a sophisticated computerized database? How did the computerized database evolve? This paper defines what we mean by a database. It traces the evolution of the database, from its start as a non-computerized set of related data, to the, now standard, computerized RDBMS (relational database management system). Early computerized storage methods are reviewed including both the ISAM (Indexed Sequential Access Method) and VSAM (Virtual Storage Access Method) storage methods. Early database models are explored including the network and hierarchical database models. Eventually, the relational, object-relational and object-oriented databases models are discussed. An appendix of diagrams, including hierarchical occurrence tree, network schema, ER (entity relationship) and UML (unified modeling language) diagrams, is included to support the text. This paper concludes with an exploration of current and future trends in DBMS development. It discusses the factors affecting these trends. It delves into the relationship between DBMSs and the increasingly popular object-oriented development methodologies. Finally, it speculates on the future of the DBMS.