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Computers:
Tools for an Information Age
Chapter 13
Database Management Systems:
Getting Data Together
Copyright © 2003 by Prentice Hall
Objectives
Describe the hierarchy of data
Explain the differences between files and
databases
List the four database models
Describe the concept of data integrity
Describe the functions of a database
management system
Copyright © 2003 by Prentice Hall
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Objectives
Describe the process of creating a
database in general terms
Compare and contrast relational and
object-oriented databases
Explain what a data warehouse is and how
it differs from a database
Copyright © 2003 by Prentice Hall
3
The Hierarchy of Data
Field – a group of one or more characters that has a
specific meaning


The smallest meaningful unit of data
Describes one characteristic of a person, place, or thing
Record – the set of fields containing data about a
person, place, or thing
File – a collection of related records
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4
Files and Databases
Traditionally, information systems were
developed with a file processing approach
Database approach creates separate files
for each entity
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Database Models
Define the way a database organizes data
Four main models




Hierarchical
Network
Relational
Object-oriented
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Data Integrity
Refers to the degree to which data is
accurate and reliable
Integrity constraints – rules all data must
follow

If integrity constraints are not followed, the
data is unreliable
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Database Management
Database Management System (DBMS) –
allows you to create a database and enter,
modify, and retrieve data as needed
Available at all levels


Sophisticated systems for a mainframe
environment
Inexpensive, easy-to-use personal computer
systems
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Database Features
Data dictionary
Data maintenance
Data retrieval
Concurrency control
Security
Backup and recovery
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Creating and Using a Database
Creating the database
Determining the table structure
Setting up the file structure
Entering the data
Using the database
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The Object-Oriented Database
Model
Designed to manipulate complex data
types

Examples include maps and audio and video
files
The object is the main focus
Designed to incorporate object-oriented
programming with large amounts of
complex data
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Data Warehouses
Contain data that has been captured in
company databases

Can contain data that has been gathered from
external sources
Use a variety of analytical tools
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