1. Week 02 - Introduction to Data Modelling
INFOSYS 222

2. Agenda Agenda Introduction The relational data model Exercises
Introduction to ERWin

3. ion Introduction Who we are What could you expect from us
What do we expect from you

4. Lab Schedule Lab Schedule Week Lab 02 Introduction 03 ER diagram 04
Data modelling 05
Workshop 06
Normalisation 07
SQL 08 09 10 11
Data warehouse 12
No lab

5. The Relational Data Model Demo – The BookStore Model

6. The Relational Data Model
Table/ Entity/ Relation
Attribute / Column/ Field
Values/ Data
Rows / Tuple

7. The Relational Data Model
Primary Key
Domain/ Data Type

8. Microsoft Access It is part of Microsoft Office
A desktop implementation of RDBMS
It has its own version of SQL
It has features beyond the requirements of a RDBMS, like Forms and Reports

9. Exercises How many rows are there in the Books table?
Which column(s) in the Orderlines table is/are the key(s)?
Why author_name is not ideal to be used as a key for the Authors table?
Which tables are related to the Books table?
What advantages are there in separating Authors and Publishers as individual tables instead of just columns in the Books table?
List the steps needed to track what Emily Jones had ordered

10. ERWin - Start Menu and Toolbars
The model explorer pane on the left – for a text based view of the data model
The diagram window pane on the right - a graphical view of the data model
Change model properties to IE
Model-> Model Properties -> Notation
This is the notation for this class

11. New Model
3 types
1. Logical: A conceptual model that includes entities, relationships, and attributes
2. Physical: A database specific model that contains relational tables, columns and associated data types
3. Logical/Physical: A single model that includes both the conceptual level objects as well as physical level tables
You will learn more about each type as you progress with your lectures
In this class we normally use Type 1

12. Model – The bookstore RDBMS schema

13. Exercises
Experiment with drawing some of the entities shown in the bookstore schema and linking them up with relationships
Start with Author and Book
The tutors will demonstrate how to add relationships in to your diagrams