1. Computers: Tools for an Information Age
Chapter 3
Database Management Systems:
Getting Data Together
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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
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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
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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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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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10. 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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11. 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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