Lecture 5:
The Relational Data Model

Outline

The Relational Data Model

Terminology

Domains

Schemas

Instances

Example

Updates

Schemas and Instances

Two Mathematical Definitions of Relations

"Relation as a set of..."

Two Definitions of Relations

From ODL to Relational Schema

Adding Non atomic Attributes

Set Attributes

Modeling Collection Types

Modeling Relationships

Option #1

Hint

Better Solution

Additional Issues

From E/R Diagrams to Relational Schema

Slide 24

Entity Sets to Relations

Relationships to Relations

Many-one Relationships

Handling Weak Entity Sets

Modeling Subclass Structure

Option #1: the ODL Approach

Option #2: the E/R Approach

Option #3: The Null Value Approach