Essential information structure diagrams and database schema design

摘要

An Information Structure Diagram (ISD) provides a detailed and exact description of the conceptual schema. It describes the semantics of a universe of discourse, such as the various object types, their associations and constraints. The ISD subsequently functions as an input to the design of the database schema, which is expressed in terms of record types, key fields and relationships. One limitation of a detailed ISD, such as the product of the Binary Relationship conceptualization model, is that in real situations it may become too complicated and difficult to understand, thus preventing users and designers of the system from “seeing the whole picture” of the information structure.We address this problem by introducing the concept of “essential-ISD” which is a concise, abstract and easily “read” ISD, containing the most important elements of the conceptual schema. Later on that essential-ISD is used to produce a “skeleton” of the database schema, which outlines the normalized record types and their associations.