Database Design &

Management

Contents (Summary)

• Concepts of Database Management• Database Designing and Modelling• Client-Server Architecture, Data Dictionaries• SQL

– DDL,DML,Views ,Constraints• Oracle SQL• Distributed Database• Object oriented database• Database Administration

Method of Delivery

• Text Books

• Reference Book/s

• Lecture Slides

• Lab work (SQL)

• Helping notes or Reference website (email)

Key to success

• Punctuality

• Hard work

• Practice

• Devotion

• Dedication

Text Book

(1) Modern Database Management By:

Fred McFadden, Jeffrey Hoffer, Mary Prescott 5th Edition, Addison Wesley

(2) Database Systems Concepts By:

Silberschatz., Korth., Sudarshan 4th Edition

(3) Database Systems By:

Thomas Connolly, Carolyn Begg 3rd Edition

(4) An Introduction to Database Systems By:

C.J.Date

What is Data ?

Definition of Data

•Data consists of Facts, text, graphics, images, sound and video segments that have meaning to user’s environment.

•Data can exist in a variety of forms: - As numbers or text on pieces of paper - As bits and bytes stored in electronic memory - As facts stored in a person's mind.

Data Type

Data is what we measureData type refers to the classification of a particular type of information

• integer• floating point• character, string• date• student record• blob (binary large object)

Data in Context

Large volume of facts, difficult to interpret or make decisions based on

INFORMATION

• Data that has been processed in such a way that it can increase the knowledge of person who uses it

Useful information that managers can use for decision making and interpretation

Data vs Information

• Data into information–Summarise data

–Data In context (table)

–Decision support

• We use Database term without distinguish data or information

ACTIVITY

• Please write down the data for cricket match bowling

• Do you get any information??

Definition of Database

“ Database is a shared collection of logically related data, designed to meet the information needs of multiple users in an organization ”

Database is designed, built, and populated with data for a specific purpose. It has an intended group of users and preconceived applications in which these users are interested.

Alternative Terminology

Data Processing Terms

Formal Terms Alternative 1 Alternative 2

Relation Table File

Tuple Row Record

Attribute Column Field

• Formal terms are mostly used for technical users.• Data processing terms are more natural for non

technical users.

Computerized File Based Processing

System

Computerized File-based Processing

File handling routines & File definition

SalesSales files

File handling routines & File definition

ContractsContracts files

File-based Systems

• A collection of application programs that perform services for the end users (e.g. reports).

• Each program defines and manages its own data.

Three file processing systems

Duplicate Data

Limitation of Computerized File-based Approach

• Separation and Isolation of data• Each application maintains its own set of data. • Users of one application may be unaware of potentially

useful data held by other applications.Duplication of data (data redundancy)• Same data is held by different files.

Limited Data SharingNo centralized control of data

Lengthy Development TimesProgrammers must design their own file formats

Excessive Program Maintenance80% of information systems budget

Limitation of File-based Approach

• Accessibility• Data is stored using programs that are written in

different languages and format• Cannot easily access other files due to incompatible file

format.• No control over access and manipulation of data beyond

that imposed by application programs.• Hard Coded Queries (Data dependence)

• File structure and all definition of data are defined in the application program code.

• Programs are written to satisfy particular functions / requirements.

• Any new requirement needs a new program.

Problems with Data Dependency Each application programmer must maintain

their own data Each application program needs to include

code for the metadata of each file Each application program must have its own

processing routines for reading, inserting, updating and deleting data

Lack of coordination and central control Non-standard file formats

Problems with Data Redundancy

• Waste of space to have duplicate data

• Causes more maintenance headaches

• The biggest Problem: – When data changes in one file, could

cause inconsistencies

– Compromises data integrity

Database Processing System

SOLUTION:SOLUTION:

Database Processing

Sales

ContractsApplication

Contracts

Database

SalesApplication

DBMS

The DATABASE Approach

• Central repository of shared data• Data is managed by a controlling

agent• Stored in a standardized, convenient

form

Requires a Database Management System (DBMS)

Database Management System

DBMS manages data resources like an operating system manages hardware resources

DBMSDBMS Databasecontainingcentralized

shared data

Application#1

Application#2

Application#3

Database Management System (DBMS)

A collection of programs that enables users to define,create and maintain and control access to the database.

General-purpose software system that facilitates the processes of defining, constructing and manipulating databases for various applications.

Defining - specifying data types, structures, constraints.Constructing - storing of dataManipulation - querying, updating and reporting.

Popular DBMS In The Market

Sybase SQL Anywhere

Informix Dynamic Server

Borland Interbase

Database Management System

• A DBMS is a data storage and retrieval system which permits data to be stored non-redundantly while making it appear to the user as if the data is well-integrated.

Advantages of Database Approach

• Program-Data Independence – Metadata stored in DBMS, so applications don’t need to

worry about data formats– Data queries/updates managed by DBMS so programs

don’t need to process data access routinesResults in: increased application development and

maintenance productivity

• Minimal Data Redundancy– Leads to increased data integrity/consistency

Advantages of Database Approach

• Improved Data Sharing– Different users get different views of the data

• Enforcement of Standards– All data access is done in the same way

• Improved Data Quality – Constraints, data validation rules

• Better Data Accessibility/ Responsiveness– Use of standard data query language (SQL)

• Security, Backup/Recovery, Concurrency– Disaster recovery is easier

Costs and Risks of the Database Approach

• Up-front costs:– Installation Management Cost and Complexity– Conversion Costs– Cost of DBMS– Additional hardware costs.

Ongoing Costs:– Requires New, Specialized Personnel– Need for Explicit Backup and Recovery– Higher impact of a failure

• Organizational Conflict:– Old habits die hard

The Range ofDatabase Applications

• Personal Database – standalone desktop database• Workgroup Database – local area network (<25 users)• Department Database – local area network (25-100

users)• Enterprise Database – wide-area network (hundreds

or thousands of users)

Personal Computer Database

Workgroup database with local area network

An enterprise data warehouse

Components of DBMS Environment

1. HardwareCan range from a PC to a network of computers.

2. SoftwareDBMS itself and operating system, including any network software if network is being used.

3. DataIncludes actual data used by the organization, and description of data (schema). Also a system catalog contains data such as the names of authorized users.

Components of DBMS Environment

4. ProceduresInstructions and rules that should be applied to the design and use of the database, and the use of the DBMS.

5. PeopleData & Database AdministratorDatabase Designer :- Logical & PhysicalApplication ProgrammersEnd Users

DBMS Environment

Software

Hardware

Procedures

People

Machine Human

Data

Bridge

Database System Environment

Users/Programs

Application Programs/Queries

Software to Process Queries/Programs

Software to Access Stored Data

Stored DatabaseDefinition

Stored Database

Evolution of DB Systems

• Flat files - 1960s - 1980s• Hierarchical – 1970s - 1990s• Network – 1970s - 1990s• Relational – 1980s - present• Object-oriented – 1990s - present• Object-relational – 1990s - present• Data warehousing – 1980s - present• Web-enabled – 1990s - present

Summary

• Course Contents• Data• Information• Data Vs Information• Database Terms• DBMS• Advantages• Disadvantages of DBMS • Database Terms• Comparison of Computerized File Based Processing

System & Database System