Entity/Relationship and Relational Models

Table of Contents

Entity/Relationship and Relational Models

Purpose of the ER Model and Basic Concepts

Entity

Relationship

Attribute

Keys

ER Diagrams

Binary Relationships and Their Functionality

Binary Relationships and ... (Cont.)

Binary Relationships and ... (Cont.)

Binary Relationships and ... (Cont.)

Binary Relationships Involving One Entity Set

Non-Binary Relationships

Non-Binary Relationships (Cont.)

Non-Binary Relationships (Cont.)

Non-Binary Relationships (Cont.)

Functionality in Non-Binary Relationships

Relationships As Entities

Relationships Having Attributes

Relationships Having Attributes

Relationships Participating in Relationships

Strong and Weak Entities

Strong and Weak Entities (cont.)

The ISA Relationship

A Sample Design

A Small Comprehensive Application

A Small Comprehensive Application (cont.)

The ER diagram for the application

From an ER Diagram to a Relational Database

From Strong Entities to Relations

From Weak Entities to Relations

From Relationships to Relations

From Relationships to Relations (Cont.)

The Relational Database

Conclusions

Topics Covered in the Unit:

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