Quan Zhou

Section O0A

Book: Introduction to System Analysis and Design.

Author: Igor  Hawryzkiewycz

Reference No. T 57.6 H38 199la

Chapter:  Chapter  7

            This chapter described methods used to develop models of system data during systems analysis. The goal at this early stage is to capture the important characteristics of data. This is done by using a high-level semantic model.

            This chapter described how entity-relationship (E-R) modeling techniques are used to develop such a model. Later in design, some further refinements are made to the E-R model. This model is then refined by converting it to a relational model. The relational model provides a number of criteria to construct normal from relations. The chapter also discussed the relationship between the E-R model and DFD diagrams and how this can be used to ensure that correct and complete models are developed during analysis