1. Database Design Using the REA Data Model
Chapter 17

2. 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.

3. Database Design Process

4. 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

5. 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)

6. REA Basic Template

7. 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

8. 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)

9. 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