qm 433 - chapter 1 database fundamentals version 10th ed · dr k. rouibah / dept qm & is...

Dr K. Rouibah / dept QM & IS Chapter 1 (433) Database fundamentals 1

QM 433 - Chapter 1

Database Fundamentals

Version 10th Ed

Prepared by Dr

Kamel Rouibah / Dept QM & IS

www.cba.edu.kw/krouibah

http://www.cba.edu.kw/krouibah

Objectives

Define terms and review basic concepts related to database

management

Name limitations of conventional file processing

Explain advantages of databases

Identify costs and risks of databases

List components of database environment

Identify categories of database applications

Describe database system development life cycle

Explain roles of individuals

Describe evolution of database systems

Introduce students to components of DBMS

Explain the three-schema architecture for databases Dr K. Rouibah / dept QM & IS Chapter 1 (433) Database fundamentals 2


Process view vs data view (Summary QM 331)

• Process view

– Concentrates both on flow, use and transformation of data

– Focuses on what the system is supposed to do

– Shows the sequence of steps (activities)

– Tracks data from source to final destination (output)

– But, does not specify the structure of data

• Data view

– Focuses on the data and its structure the system needs to operate

– Separates application programs and the data used by programs (e.g. students

and students attributes)

– Approach is independent of where and how data are used in a system

– Data designed for the whole enterprise

QM 433 will focus SOLELY on the data view

BASIC CONCEPTS AND DEFINITIONS



Data hierarchy: Basic definition: Bit, byte, field, record,

file and database (summary of past MIS courses)


Basic concepts and definitions: Two types of data

• Database: organized collection of logically related data

• Data: stored representations of meaningful objects and

events that include structured and unstructured data

• Structured data

– Numeric; e.g. 2013

– Characters; e.g. name, registration, student ID

– Date: 12th of February 2013

• Unstructured data: multimedia

– Documents, e.g. a PDF or Word document

– Maps (see. Google Earth)

– Photographic image

– Sound

– Video


Basic concepts and definitions: Metadata

• Metadata

– Data that describes the properties or characteristics of end user

data and the context of that data

– Separate data from its properties

• Metadata enables designers and users to understand:

– What data exist?

– What the data mean?

– What the fine distinctions are between similar data items?

• Example see MS Access (field properties)


Example of metadata


Basic concepts and definitions: information

• Information: data that have been processed to increase knowledge

and is useful in decision making

• Two types of information

Data in context Summarized data

We can easily recognized class Roster

TRADITIONAL FILE PROCESSING

SYSTEMS



Disadvantages of traditional file management

• Similar disadvantages were seen in chapter 5 (QM 240) and chapter

1 (QM 331)

• File management a way of collecting and maintaining data in an

organization

• Each functional area (department) creates and maintains its own

data files and programs.

• Files allow the creation of a single database

• Only one file is accessed at a time


Example of file management: What problems are shown in this

figure?

Relation

Are missing

Data is redundant


Disadvantages of traditional file management (cont')

• Program-data dependence

– All programs maintain metadata for each file they use

– Close relationship exists between data stored in traditional files

and the software programs that update and maintain those files.

• Data duplication (redundancy)

– The presence of duplicate data in multiple data files leads to data

inconsistency (عدم التوافق)

– Waste of space high maintenance costs

– Each application programmer must maintain his/her 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


Disadvantages of traditional file management (cont')

• Limited data sharing

– Information is available in different files and different

parts of the organization

– No centralized control of data; data or information

cannot flow freely from one part to another in the

organization

• Length development time

– Related to previous, there is a need for extra

programming efforts to let users access other files not

under their control

High Maintenance cost

• Excessive program maintenance or lack of flexibility

– 10% of time are devoted to debugging problems

– 10% are concerned with changes in data, files, reports, hardware, or system software.

– Up to 80% of all maintenance work consists of making user enhancements, improving documentation, and recoding system components for greater processing efficiency.

– Consume 80% of information systems budget


The DATABASE Approach

• Data models – Graphical system capturing nature and relationship of data

– See more in chapter 2 and 3

• Entities

– Noun describing a person, place, object, event, or concept

– Composed of attributes

• Relationships

– Between entities (Unary, binary, ternary)

– 1-to-1,one-to-many (1:M) or many-to-many (M:N)

• Attributes

– Pieces of information that describe entities


The DATABASE Approach

• Instances

– Elements that compose entities

• Types of data models

– Relational database model: establish relationship between

entities using a common field

– Object model

• Database application

– is an application program (or set of related programs) that is

used to perform a series of database activities (create, read,

update, and delete) on behalf of database users



Database Management System (DBMS)

DBMS manages data

resources like an operating

system manages hardware

resources

• DBMS is a software system that is used to create, maintain, and

provide controlled access to user database

• DBMS is used to connect three different database applications

Order Filing

System

Invoicing

System

Payroll

System

DBMS

Central database

Contains employee,

order, inventory,

pricing, and

customer data

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Advantages of the Database Approach

• Program-data independence

• Planned data redundancy

• Improved data consistency

• Improved data sharing: different users views (e.g. students, doctors, etc.)

• Increased application development productivity

• Enforcement of standards

• Improved data quality: poor data is a serious problem and Estimation of TDWI (The Data Warehousing Institute) $600 billions/year

• Improved data accessibility and responsiveness: no need for programming experience

• Reduced program maintenance

• Improved decision support

20

Costs and Risks of the Database Approach

• New, specialized personnel

– Database designer, database administrator who needs continuous

training

• Installation and management cost and complexity

– Software suite such as Oracle need installation, maintenance, upgrade,

• Conversion costs of legacy system is too high

– Legacy system are old systems (or databases) that have been in

existence for long time ago and the conversion to new databases is too

high

• Need for explicit backup and recovery

– Corporate databases are needed with almost zero downtime (e.g. Borsa)

• Organizational conflict

– Require consensus on issue such as data definition and ownership and

responsibilities need strong top management support

Components of the database environment



Component of the database environment

• Computer-Aided Software Engineering Tools

– CASE tools automate curtains design functions, e.g. generate ERD and the

code (e.g. MS Visio)

• Repository

– Centralized storehouse of metadata, data relationship, screen and report

formats, and other system components

– Include additional metadata to manage databases (see more in chapter 11

Administration)

• DBMS

– Used to create, maintain, and provide controlled access to user database

• Database

– Collection of data organized to service many applications at the same time by

storing and managing data so that they appear to be in one location


Component of the database environment (cont’)

• Application Programs

– The software program (or set of related programs) that is used to perform a

series of database activities (create, read, update, and delete) on behalf of

database users

• User Interface

– Text and graphical displays to users

• Data and Data Administrators (see more in Chapter 11)

– Personnel responsible to maintain the database

• System Developers

– Personnel responsible to design the databases and software (e.g. system

analysts and programmers)

• End Users

– People who use the applications and databases

The Range of Database Applications



Personal Database

• Standalone desktop database designed to support one user

• E.g. data bases developed by my students in QM 433

• Example of key issue management

– Should the application be purchased from outside vendor or developed in-house?

– What commercial DBMS product should be used for the application?

Two-tier • A small DB to be used by Workgroup LAN for less than 25 users to

share data

• Support the collaborative efforts of the team using computers connected to a LAN such as developer, system analyst, project manager

• DB is stored on a computer called database server

• Each user computer has a copy of a light application that provides him with user interface and business logic (e.g. algorithms that handle information)

• Example: DB used at our college to book a specific LAB for a specific instructor


Dr K. Rouibah / dept QM & IS Chapter 1 (433) Database development

process

29

Three-tiered database location architecture

• In large information systems, data may be stored in different

computers locations (or tiers)

• Processing (application) of the data from a database may occur at

different locations in order to take advantages of the processing

speed, ease of use of programming on different computers

platforms too

• Browser-based interface in conjunction with company database is

increasingly used to ease transactions between the web browsers

the back-end database

• Data could reside on a client server, on a application server, on

a web server, and on a database server

Three-tiered client/server database architecture


Store Applications

Store Data related

To different application

Enterprise Database

• Serve the entire organization (or several departments)

• Organization may have several enterprise DBs

• Databases used at a large scale (hundreds or thousands of users)

• It is based on WAN

• Two major development: ERP and data warehousing systems


Enterprise Resources Planning (ERP) systems

• Information systems that integrate and coordinate key internal

processes of the firms, integrating data from different business

functions (manufacturing, finance, sales, marketing, inventory,

accounting, human resources)


Data Warehouse Systems

• Is a database, with reporting and query tools, that stores current and

historical data extracted from various operational systems, for the

entire organization, and consolidated for management reporting

and analyzing (e.g. CRM)


Internet, Intranet and extranet

• Internet: network of connected computer servers over the world

• Intranet: private company network accessed only by employees

• Extranet: Intranet with extended authorization to suppliers and customer

• Business-to-consumer (B2C)

• Issues to consider

– Which technologies to use?

– Security/privacy protection

– Managing huge volumes of data from Internet transactions

– Maintaining data quality


Evolution of database technologies



Types of databases

Network DBMS AND Hierarchical DBMS

• Used to develop first generation of DBMS

• Appeared in 1970 and several systems continue to be used up to now

• Difficult to access data, based navigational record-at-a-time procedure

• Legacy system is a system that has been in existence for a long time (in a

mainframe) and that continues to be used to avoid the high cost of replacing or

redesigning it (QM 240).

Relational DBMS [1980] [General culture]

• Manage mainly structured data (text and numbers)

• Received wide commercial acceptance in 1980

• Data are represented in tables

• Easy data access for non programmers through SQL, 4th generation language

Types of database

Object oriented DBMS AND Object relational DBMS (cont’)

• Used to develop the 3rd generation of DBMS

• Appearance and important because of of client/server architecture,

data warehousing , and internet applications

• Large use of structured data (e.g. accounting) and multimedia data

and applications (sound, images and videos)

• Introduced in 1980, but largely accepted in 1990s

• See more in chapter 14 and 15

• Because companies manage vast amount of structured and

unstructured data, vendors are developing Object Relational

DBMS


The database development process



process

39

System Development Life Cycle

Project

identification

and selection

Project initiation

and planning

Analysis

Logical design

& physical design

Implementation

Maintenance

SDLC: the traditional

methodology used to develop,

maintain, an replace information

system


process

40

Database development process during SDLC


process

41

Enterprise modeling

• It is performed during the 1st phase of SDLC “Identification and

selection”

• Enterprise data model describes the entities in an organization and

the relationship between these entities

• Analyze the current business and determine their needs in term of

databases and information systems

• Review existing information systems and databases

• Identify what data is available and what other data need to be added

to these systems

Enterprise modeling

• Use Planning Matrix (see next) that describe interrelationships between planning objects

– Business function to data entities

– IS-to-data entity

– IS-to-business objective

• Output: Select one project for database development


Example of data entity and business function


process

43

Exercise

• Question: Draw the enterprise modeling for CBA by

generating the same table as before

• Remark: the model should include all entities in the

present time and the future



process

45

Conceptual data modeling (2nd phase of SDLC- Initiation

an planning)

• System analyst will generate a conceptual data model

• It is also called “conceptual schema” or “entity

relationship diagram” (see chapter 2 and 3)

• The E-R model project highlights only high level

categories of data (entities) and major relationships that

are useful only for the specific project (not for the

enterprise)


process

46

Conceptual data modeling (3rd phase of SDLC-Analysis)

Two activities

• System analyst will specify the conceptual data model i(for the selected project) in

term of

– Attributes of the entities

– Relationships between the identified entities

• Specify the rules that dictates the integrity of the data,

– It is also called conceptual schema

• Remark:

– But the E-R model is just a preliminary model since it will be subject of modifications

based on subsequent SDLC activities

– Why: because of missing elements or errors when designing transactions, reports,

display or inquiries (see more in the QM 471: project in IS)

– Conceptual data modeling is a top down process, i.e. it is driven from a general

understanding of the business area, and not from specific information processing

activities


process

47

Logical database design (4rd phase of SDLC)

Two important activities

• Transform the conceptual data model to a logical data model

– Logical data model describes the data in term of the data management technology that will be used to implement the database

– E.g. if a relational technology will be used the transformation process is called normalization (see chapter 4 and 5), i.e. it must be transformed into a relational data model but independent of any database technology

• Design each computer program in term of

– Input, output format, reports, display, and inquiries supported by the database

– Description is made independent from any particular database management system

• Remark

– This is a “bottom-up analysis”, i.e. system analyst verifies exactly what data are to be maintained in the DB and the nature of those data as needed for each transaction, reports, and so forth

– Logical model might lead to modification of the conceptual data model


process

48

Physical database design and definition (5rd phase

of SDLC)

• It is dependent of the DBMS that will be used to implement the database

• This task is carried based in coordination with all other aspects of the physical

information systems

– Programs

– Computer hardware

– Operating systems

– Data communication networks

• System analyst will specify

– The organization of physical record

– Choice of file organization (see Three-Tiered database location)

– Use of indexes

– Where to store data “centralized or decentralized”

– Decision support reports

– Security,

– etc


process

49

Implementation of the Database (6rd phase of

SDLC)

• Write, test and install the programs that process the data

• There are many available programming languages, e.g.

Visual Basic can be used to generate high complex MS

Access database

• Produce effective display and reports

• Finalize the database users’ documentation

• Put the database in production

• Backup the database in order to ovoid losing data


process

50

Database maintenance (7rd phase of SDLC)

• Modify (add, delete, change) the structure of database

• Modification is carried out for three reasons:

– Meet new business requirements

– Correct errors in the database design,

– Improve the processing speed of the database

applications


process

51

Exercise: fill in this table by putting Yes or No /

Four important data models in the database

All entities? All

attributes?

Technology

independent

?

DBMS

independent

?

Record

Layouts?

Enterprise

model

Conceptual

model

Logical

model

Physical

model


process

52

Alternative information system development approaches

(see more in QM 240)

• SDLC has several disadvantages

• In house development

– Rapid Application Development (e.g. Prototyping, see figure

1.11)

– Prototyping: an iterative process of systems developments in

which requirements are converted to a working system that is

continually revised through close work between analysts and

users

Alternative information system development approaches

• Agile software development: An approach to database

development that emphasizes

– Individuals and interactions over processes and tools

– Working software over comprehensive documentation

– Customer collaboration over contract negotiations, and

– Response to change over the following a plan”

• Other Alternative information system development approaches

– Application Software Package: e.g. Oracle Suite

– Outsourcing



process

54

Different people

have different

views of the

database…these

are the external

schema

The internal

schema is the

underlying design

and

implementation

Three schema architecture view of a manager

or external user

View of data

architect or data

administrator

view of a database

administrator


process

55

Three schema architecture

• Physical Schema

– Physical structures – Will be covered in chapters 6 and 7

• Conceptual Schema

– E-R models – Will be covered in chapters 2 and 3

• External Schema (in the lab with Heba)

– User Views

– Subsets of Conceptual Schema

– Can be determined from business-function/data entity matrices

– DBA determines schema for different users


process

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Managing the People Involved in database development seen in

previous courses (QM 240) and (QM 331)

• Business analyst

• Systems analysts

• Database analysts and data modelers

• End-users

• Programmers

• Database architect

• Data administrators

Project managers

• Other technical experts (Network administrators, security, etc.)

End of chapter 1
