ERRDS: A Case Tool to Generate an ER Data Model from a Relational Database Schema

Abstract

A relational database (RDB) schema is a description of database requirements in terms of a set of relations and a set of integrity constraints. An Entity- Relationship(ER) data model is a high-level conceptual data model that is used frequently for the conceptual design of databases. ER data models represent a concise description of users' data requirements without including implementation details. Because of that, ER data models are usually used to communicate with nontechnical users since they are easier to understand. Some relational database designers used the concept of a universal relation and perform normalization to come up with the relational database schema, without developing an ER data model. We advocate that the best practice for a relational database design is to start with developing a conceptual schema like an ER data model and then map it to a relational database schema (as many CASE tools support). In this article, a case tool to perform the reverse process, which is generating an ER data model from a relational database schema, is presented. This tool is very useful in obtaining a conceptual schema from a relational database schema. This tool can also be thought of as a kind of reverse engineering case tool that aids in the reverse engineering of legacy databases to consider new implementation technology options.