Database Design Using the REA Data Model Chapter 17

Learning Objectives Discuss the steps for designing and implementing a database system. Use the REA data model to design an AIS database. Draw an REA diagram of an AIS database. Read an REA diagram and explain what it reveals about the business activities and policies of the organization being modeled.

Database Design Process

Data Modeling Process of defining a database so that it faithfully represents all aspects of the organization, including its interactions with the external environment. Entity-relationship (E-R) diagrams REA data model

REA Modeling Resources Events Agents Things that have economic value to the organization (e.g., inventory, cash) Events Various business activities that management wants to collect information on Agents People and organizations that participate in events (both internal (e.g., employees) and external (e.g., customers/vendors) to the organization)

REA Basic Template

Creating an REA Model Identify relevant events Give-get exchange (economic duality) Identify resources and agents Resource reduced in give event Resource acquired in get event Determine cardinalities of relationships Nature of the relationship between the two entities

Cardinality Notation Methods Graphical symbols Graphical symbols represent minimum– maximum cardinalities (Min, Max) notation Pairs representing the minimum–maximum cardinalities UML notation Maximums only (Microsoft Access)

Key Terms Data modeling Entity-relationship (E-R) diagram REA data model Resources Events Agents Cardinalities Minimum cardinality Maximum cardinality One-to-One (1:1) relationship One-to-Many (1:N) relationship Many-Many (M:N) relationship