Database and Management-Chapter1 Part 1

8/10/2019 Database and Management-Chapter1 Part 1

1/38


2/38

Introduction

Today, more than at any previous time,

the success of an organization depends on its

ability to acquire accurate and timely data

about its operations, to manage this data

effectively, and to use it to analyze and guide

its activities.


3/38

Definition of Terms:

Data

It is a stored representation of objects and events that have

meaning and importance in the usersenvironment.

referred to facts concerning objects and events that could be

recorded and stored on computer media. Structured: numbers, character, dates

Unstructured/Multimedia: images, sound, video segments,

documents, maps, emails

Information

It is a data that have been processed in such a way as to increase

the knowledge of the person who uses the data.


4/38

Figure 1-1a Data in context

Context helps users understand data


5/38

Graphical displays turn data into useful information

that managers can use for decision making and

interpretation

Figure 1-1b Summarized data


6/38

Definition of Terms: (Contd)

Database

It is an organized collection of logically related data.

MetadataThese are data that describe the properties or characteristics of

end-user data and the context of that data.

It is also refer to Dataabout data.


7/38

Descriptions of the properties or characteristics of the data,

including data types, field sizes, allowable values, and data

context


8/38

Hierarchy of Data

Bit

It is the smallest unit of data (0 and 1).

Byte

It consist of 8 bits; collection of bits; it is a character.

Field It is a group of characters that form a word

Record

It is a collection of related field.

Files It is a collection of records.

Database

It is collection of interrelated files.


9/38

File Processing Systems

A file processing system is the process of creating,

storing and accessing content of files.

It is also a collection offiles

and programs thataccess/modify these files. Typically, new files and

programs are added over time (by different

programmers) as new information needs to be stored

and new ways to access information are needed.

File

It is a collection of related records.


10/38

Figure 1-2:Old file processing systems

at Pine Valley Furniture Company


11/38

Disadvantages of File Processing

Program-Data Dependence All programs maintain metadata for each file they use

Duplication of Data

Different systems/programs have separate copies of the samedata

Limited Data Sharing No centralized control of data

Lengthy Development Times Programmers must design their own file formats

Excessive Program Maintenance 80% of information systems budget


12/38

Figure 1-2:Old file processing systems


Data Dependency / Duplicate Data


13/38

Problems with Data Dependency

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

Lack of coordination and central control

Non-standard file formats


14/38

Problems with Data Redundancy

Waste of space to have duplicate data

Causes more maintenance headaches

The biggest problem:

Data changes in one file could cause inconsistencies

Compromises in data integrity


15/38

SOLUTION:

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)


16/38

Database Management System

A Database Management Systems is a software systemthat is used to create, maintain, and provide controlledaccess to user databases.

It facilitates the processes of defining, constructing, and

manipulating

databases for various applications. Defining a database involves specifying the data types,

structures, and constraints for the data to be stored in thedatabase.

Constructing the database is the process of storing the data itselfon some storage medium that is controlled by the DBMS.

Manipulating a database includes such functions as querying thedatabase to retrieve specific data, updating the database toreflect changes in the miniworld, and generating reports from thedata.


17/38

Order Filing

System

Invoicing

System

PayrollSystem

DBMSCentral database

Contains employee,

order, inventory,

pricing, and

customer data

Figure 1-3:DBMS approach



18/38

Advantages of the Database

Approach

Program-Data Independence

The separation of data descriptions (metadata) from the

application programs that use the data.

Planned Data Redundancy

Improved Data Consistency Improved Data Sharing

It facilitate a User Viewwhere it is a logical description of

some portion of the database that is required by a user to

perform some task.

Increased Application Development Productivity

Enforcement of Standards


19/38

Advantages of the Database

Approach (contd)

Improved Data Quality A constraint is a rule that cannot be violated by database users.

Improved Data Accessibility and Responsiveness

Reduced Program Maintenance

Improved Decision Support


20/38

Costs and Risks of the Database

Approach

New, Specialized Personnel

Installation and Management Cost and Complexity

Conversion Costs

Need for Explicit Backup and Recovery Organizational Conflict


21/38

Elements of the Database

Approach Data models

Graphical systems used to capture the nature and relationships

among data. (Entity, Attributes, Relationships)

Enterprise Data Modelhigh-level entities and relationships forthe organization

Project Data Modelmore detailed view, matching data structurein database or data warehouse.

Relational DatabasesA database that represents data as a collection of tables in which

all data relationships are represented by common values in

related tables.


22/38

Elements of the Database

Approach Database Applications

Application programs used to perform database activities for

database users.

Activities: Createto add new data to the database.

Readto read current database data.

Updateto modify current database data.

Deleteto delete current data from the database.


23/38

Figure 1-4:Components of the Database Environment


24/38

Components of the

Database Environment Computer

Aided Software Engineering (CASE) Tools

Software tools that provide automated support for some portionof the systems development process.

Repository

A centralized knowledge base of all data definitions, datarelationships, screen and report formats, and other systemcomponents; centralized storehouse of metadata.

Database is an organized collection of logically related data, usually

designed to meet the information needs of multiple users in anorganization; storehouse of the data

Database Management System (DBMS) is a software system that is used to create, maintain, and provide

controlled access to user databases; software for managing the

database


25/38

Components of the

Database Environment (contd) Application ProgramsComputer-based application programs are used to create and

maintain the database and provide information to users; softwareusing the data

User InterfaceText and graphical displays to users

Data/Database AdministratorsPersonnel responsible for maintaining the database

System DevelopersPersonnel responsible for designing databases and software

End UsersPeople who use the applications and databases


26/38

The Range / Categories of

Database Applications

Personal Databases

It is designed to support one user. The purpose of these

databases is to provide the user with ability to manage (store,

update, delete, and retrieve) small amounts of data in an efficient

manner.

Two-Tier Client/Server Database

It is a relatively small team of people (typically fewer than 25

persons).


27/38

Figure 1-5: Two-Tier Client/Server Database


28/38


Database Applications (contd)

Multitier Client/Server Databases

It is intended to support a department (such as marketing or

accounting) or a division (such as a line of business), which is

generally larger (typically between 25 and 100 persons).


29/38

Figure 1-6: Multitier Client/Server Database


30/38



Enterprise Applications

Enterprise resource planning (ERP) systems

A business management system that integrates all functions

of the enterprise, such as manufacturing, sales, finance,

marketing, inventory, accounting, and human resources. ERPsystems are software applications that provide the data

necessary for the enterprise to examine and manage its

activities.

Data warehousing implementationsAn integrated decision support database whose content is

derived from the various operational databases.


31/38

Figure 1-7: An enterprise data warehouse


32/38



Web-Enabled Database

Extranet communication

Business-to-Consumer (B2C)

Business-to-Business (B2B)

Intranet communication


33/38

Table 1-8: Summary of Database Applications


34/38

Evolution of Database Systems

Figure 1-9: Evolution of database technologies


35/38


(Contd)

Human beings began to store information very long ago.

Where programming became the foundation of creating

enterprise computer systems. The systems developed, needed

to store its data somewhere and the programmers designed

more or less proprietary and specialized solutions for thispurpose.

1960S

Two models:

Network Model, was designed by Charles Bachman at

General Electric called Integrated Data Store and standardized

by the Conference on Data Systems Languages (CODASYL) .

Hierarchical Model, Rockwell collaborates with IBM to create

the Information Management System (IMS).


36/38


(Contd) 1970s

Ted Codd at IBMs San Jose Lab proposed relational models.

Peter Chen defined the Entity-relationship(ER) model (1976)

1980s

Structured Query Language (SQL), became the standard querylanguage.

Object-oriented DBMS (OODBMS) develops. (1985)

1990s

Incorporation of object-orientation in relational DBMSs. (Object-

relational)

First Internet database applications (1995)

2000s

Database applications continue to grow, the three leading database

companies in the western world are Microsoft, IBM, and Oracle.


37/38


(Contd)

Figure 1-10: Pictorial representation of Database

Evolution over decades


38/38

The END

Documents

Database and Management-Chapter1 Part 1