Entity-relationship modeling

Entity-Relationship Modeling: Historical Events, Future Trends, and Lessons Learned
Peter P. Chen
Computer Science Department Louisiana State University Baton Rouge, LA 70803, USA E-mail: pchen@lsu.edu

Abstract. This paper describes the historial developments of the ER model from the 70’s to recent years. It starts with a discussion of the motivations and the environmental factors in theearly days. Then, the paper points out the role of the ER model in the Computer-Aided Software Engineering (CASE) movement in the late 80’s and early 90’s. It also describes the possibility of the role of author’s Chinese culture heritage in the development of the ER model. In that context, the relationships between natural languages (including Ancient Egyptian hieroglyphs) and ER concepts areexplored. Finally, the lessons learned and future directions are presented.

1 Introduction
Entity –Relationship (ER) modeling is an important step in information system design and software engineering. In this paper, we will describe not only the history of the development of the ER approach but also the reactions and new developments since then. In this perspective, this paper may be a little bitdifferent from some other papers in this volume because we are not just talking about historical events that happened twenty or thirty years ago, we will also talk about the consequences and relevant developments in the past twenty-five years. At the end, we will talk about lessons learned during this time period. In particular, we intend to show that it is possible that one concept such as the ERconcept can be applied to many different things across a long time horizon (for more than twenty-five years) in this fast-changing Information Technology area. This paper is divided into 8 sections. Section 1 is the Introduction. In Section 2, the historical background and events happened around twenty-five years ago will be explained. For example, what happened at that time, what the competingforces were, and what triggered researchers like the author to work on this topic will be explained. Section 3 describes the initial reactions in the first five years from 1976 to 1981. For example, what the academic world and the industry viewed the ER model initally? Section 4 states the developments in the next tweny years from 1981 to 2001. In particular, the role of the ER model in theComputer-Aided Software Engineering (CASE) will be discussed. Section 5 describes a possible reason for the author to come up with the ER modeling idea , that is, the author’s Chinese culture heritage. The author did not think about this particular reason until about fifteen years ago. Section 6 presents our view of the future of ER modeling. Section 7 states the lessons learned. For those of you who havesimilar experience in the past twenty-five years, you probably have recognized similar principles and lessons in this section. For those who just started their professional careers recently, we hope the lessons learned by the author will be helpful to those readers. Section 8 is the conclusion.

2 Historical Background
In this section, we will look at the competing forces, the needs of thecomputer industry at that time, how the ER model was developed, and the main differences between the ER model and the relational model. 2.1 Competing Forces First, Let us look at the competing forces in the computer software area at that time. What are the competing forces then? What triggered people like the author to work on this area (data models) and this particular topic (ER modeling)? In thefollowing, we will discuss the competing forces in the industry and in the academic world in the early 70’s, Competing Forces in the industry. There were several competing data models that had been implemented as commercial products in the early 70’s: the file system model, the hierarchical model (such as IBM’s IMS database system), and the Network model (such as Honeywell’s IDS database system)....