INTRODUCTION TO DATABASES

Chapter 1

What is a Database?

Forget the glossary! (see pages 11-12) The purpose of a database is to help

people track things of interest to them In relational databases we can start by

thinking of databases in terms of: Tables (one for each entity) Relationships (between entities)

Everything is better with an example!!!

Your job is to maintain the database

WHAT? I can’t do that! I don’t know the data structures to use, I don’t know how to organize the rows in

the tables I don’t know how to store the tables on disk

… Fine, we’ll give you a Database

Management System (DBMS)

How do I use a DBMS?

That’s what this course is all about! There are two main tasks: First, we must organize the data - the things we are

interested in - in such a way that it reflects a logical design (Modeling: First part of course)

Second, we create the database so that it reflects that model. (Implementation: Second major goal of course)

There is a third thing and it is the most ticklish job that we perform – we ADD/DELETE/MODIFY the data.

All of this is done in the language of …

SQL

Some Simple SQL

SELECT [field list]FROM [Table or Tuple List]WHERE [Constraint]

Components of a Database System

Applications

Interface to the DBMS from Applications

Database Management System which translates SQL into actions on the data.

The repository of data and META Data is the “Database”

What else is in the Database

What you need to know

Knowledge Priorities

DAVID M. KROENKE’S DATABASE PROCESSING, 10th Edition

© 2006 Pearson Prentice Hall

1-11

A Brief History of Database Processing

The Relational Database Model The dominant database model is the

relational database model – all current major DBMS products are based on it

Created by IBM engineer E. F. Codd in 1970

It was based on mathematics called relational algebra

This text examines and explains the relational database model