Database SystemsUnit # 1

Introduction & History of Database Systems

Introduction

Introduction Course Outline Project Labs Grading

Queries

What is Data? What is Database? What is DBMS?

Basics Data

Raw facts/details of a subject or universe of discourse.

DatabaseA shared collection of logically related data, designed to meet the information needs of an organization.

Database Management System (DBMS) Software that enables users to define, create and maintain the database and provides controlled access to the database

What is the importance of data?

Paradigm shift: Data driven business environment

Customer information (e.g., database Customer information (e.g., database marketing, CRM)marketing, CRM)

Competitor and marketplace Competitor and marketplace informationinformation

Current Status to identify Current Status to identify replenishment needsreplenishment needs(e.g. Stock in hand)(e.g. Stock in hand)

Knowledge and innovation (e.g., Knowledge and innovation (e.g., knowledge management, business knowledge management, business

intelligence)intelligence)

Performance of vendors Performance of vendors (e.g., supply chain management(e.g., supply chain management

History of Database Systems

First generation File based systems

Second generation Relational databases

Third generation Object relational databases Object Oriented databases ……….and others

Traditional File-Based System

““A collection of application programs that perform services for A collection of application programs that perform services for the end users such as the production of reports. Each program the end users such as the production of reports. Each program

defines and manages its own data.”defines and manages its own data.”

Traditional File-Based System

Invoice ProgramInvoice Program InvoicesInvoices

Customer AccountCustomer AccountProgramProgram

Account Account ReportReport

Customer MailingsCustomer MailingsProgramProgram

Mailing Mailing ListList

CustomerCustomerOrdersOrders

CustomerCustomerMailing Mailing

ListList

Customer Customer Accounts Accounts

FileFile

Data Redundancy

Customer Order File Invoice number Customer account number Customer name, address, city, state, zip code Order date Product code, product description, price, unit

Customer Account File Account Number Customer name, mailing address, city, state, zip code

Customer Mailing List File Customer name, mailing address, city, state, zip code

File-Based Systems - Limitations Separation and isolation of data (one file, one

program) Duplication of data Loss of data integrity - uncertainty of the correct

version of data and no consistency Data dependence - application program defines

the data Incompatibility of file formats Fixed queries/proliferation of application

programs. Little flexibility in meeting changing information needs

Database

Database can more technically be defined as:

‘Shared collection of logically related data, and a

description of that data, designed to meetinformation needs of an organization.’

OR‘Self-describing collection of integrated record.’

Database Management System (DBMS) DBMS can be defined as:

“ Software system that enables users to define, create and maintain the database and provides controlled access to the database.”

Database Management System (DBMS) contains not only the data but meta data as well i.e. data about the data

Illustrating Metadata