Chapter 9
Database Management
Professor Michael J. Losacco
CIS 1110 – Using Computers
Overview
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Define Database
Describe Database Hierarchy
Describe Database Functions
Describe Validation Techniques
List Features of Relational Databases
Explain How to Use Queries
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Database
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DBMS (Database Management System)
Organized Collection of Data
For Quick Access, Retrieval, & Use
Database Software Allows You to
Create Database
Add, Change, & Delete Data
Sort & Query Database
Print Reports
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Data & Information
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Processed Data Becomes Information
Largest Commercial Database
2 PB — Yahoo (Oracle on Unix 2010)
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Data & Information
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Data Integrity
Degree to Which Data is Correct
Database Contains Errors
Loses Integrity
GIGO (Garbage In, Garbage Out)
Cannot Get Good Information From Bad Data
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Database Hierarchy
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Database Contains Tables
Table Contains Records
Record Contains Fields
Field Contains Characters
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Database Hierarchy
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Field
Combination of One or More Characters
Smallest Unit of Data User Accesses
Characteristics
Name Uniquely Identifies Each Field
Data Type
Text
Numeric
Currency
Size
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Database Hierarchy
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Record
Group of Related Fields
Key Field
AKA Primary Key
Uniquely Identifies Each Record
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Database Hierarchy
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Table
Collection of Related Records
Each Record Contains Same Fields
Each Field Contains Different Data
Database
Group of Related Tables
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Maintaining Data
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File Maintenance
Procedure That Keeps Data Current
Add Records
When You Obtain New Data
Change Records
Correct Inaccurate Data
Update Existing Data
Delete Records
Record No Longer Needed
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Maintaining Data
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Validation
Comparing Data with Set of Rules
Reduce Data Entry Errors
Enhance Data Integrity
Types
Alpha / Numeric
Range
Completeness
Consistency
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Features
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Data Dictionary
Lists Fields For Each Table in Database
Lists Properties For Each Field in Table
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Features
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Form
On Screen Window
View Single Record
Area to Enter / View / Change Data
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Features
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Report Generator
Creates Report
Without User’s Knowledge of Programming
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Features
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Report Types
Detailed
Summary
Consolidates Data
Exception
Identifies Data Outside of Norm
Conditions Define Status Range
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Features
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Query
Request Specific Data from Database
SQL (Structured Query Language)
Specify Data to Display, Print, or Store
QBE (Query By Example)
Retrieves Records that Match Criteria
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Features
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Security
Only Authorized Users Can Access Data
Access Privileges
Define Activities Group of Users Can Perform
Read-only Privileges
User Can View Data, But Cannot Change It
Full-update Privileges
User Can View & Change Data
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Features
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Backup
Copy of Entire Database
Log
Listing of Activities that Change Contents
Places Three Items In Log
Before Image
Actual Change
After Image
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Features
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Log Example
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Database Models
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Model
Rules & Standards Defining:
How Database Organizes Data
How Users View Data
Types
Relational
Object-oriented
Multidimensional
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Database Models
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Relational
Stores Data in Tables
Consist of Rows (Records) & Columns (Fields)
Each Row has Primary Key
Related Tables Must Have Common Field
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Database Models
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Relational
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Database Models
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Object-Oriented
Stores Data in Objects
Can Contain Both Data & Actions
Advantages
Can Store More Types of Data
Can Access Data Faster
Programmers Can Reuse Objects
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Database Models
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Object-Oriented Examples
Multimedia
Images, Audio Clips, Video Clips
CAD
Engineering, Architectural, Scientific Data
Groupware
Schedules, Calendars, Memos, Reports
Hypertext
Links to Other Documents
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Database Models
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Object-Oriented Example
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Database Models
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Multidimensional
Stores Data in More than Two Dimensions
Allow Users to Analyze Any View of Data
Advantages
Consolidates Data Faster than Relational
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Database Models
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Multidimensional Examples
Data Warehouse
Comprehensive Data
Required to Analyze Data Across Enterprise
From Multiple Databases
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Database Models
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Multidimensional Examples
Data Mining
Find Patterns & Relationships Among Data
Based on Open-ended User Queries
Click Stream
Every Action Visitors Take in Web Site
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Database Development
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Process
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