Chapter 15 & 16

Conceptual and Logical Database

Design Methodology

Thomas Connolly, Carolyn Begg, Database System, A Practical Approach to Design Implementation and

Management, 4th Edition, Addison Wesley

Pg 437~ 492

Learning Outcomes

• Definition

• Conceptual database design

• Relational database - logical design

• Example

Definition• Design methodology

– Structured design approach using procedures, techniques, tools and documentation aids

• Conceptual database design– Constructing an information model, independent from

all physical consideration for an enterprise

• Logical database design– Building an organization database based on a specific

data model

Conceptual Database Design

• Entities • Relationships• Attributes (simple, no composite, no derived)• Attribute domains• Primary and candidate key attributes

– Minimal set of attributes

– Less change

– Uniqueness in the future

– Fewest characters

– Easy to use by users

Relational Database - Logical Design

• Draw ER model• Review

– Always binary with1 to many relationship

– No complex relationship

– No redundant relationship

– No recursive relationship

– No relationship with attribute(s)

Relational Database - Logical Design

• Normalize relations– Primary key– Foreign key– BCNF

• Add constraints– Domain & enterprise– Referential– Entity– legal

Relational Database - Logical Design

• Review– Organization current & future needs– All user current & future requirements– Normalization (Boyce-Codd)– Relationship (one-to-one or one-to-many)– Redundancy– Constraints

• User approval

• Document