Shelly Cashman Series Discovering Computers 2003
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Transcript Shelly Cashman Series Discovering Computers 2003
10
Database Management
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Identify the qualities of valuable
information
Describe characteristics of relational
and object-oriented databases
Discuss the terms character, field,
record, and table
Explain how to use a
query language
Identify file maintenance techniques
Understand how Web
databases work
Discuss the functions most
common to DBMSs
Understand the concept of a data
warehouse
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Database
AKA Database Management System (DBMS)
Collection of Data
Organized for Quick Access, Retrieval, & Use
Databases Allow You to
Create Database
Add, Change, & Delete Data
Sort & Query Database
Print Reports
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Data Integrity
Degree to Which Data is Correct
When Database Contains Errors, it Loses Integrity
GIGO (Garbage In, Garbage Out)
Cannot Create Correct Information From Incorrect Data
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Qualities of Valuable Information
Accurate
Verifiable
Timely
Organized
Accessible
Useful
Cost-effective
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Data Hierarchy
Database Contains Files
File Contains Records
Record Contains Fields
Field Contains Characters
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Field
Combination of One or More Characters
Smallest Unit of Data User Accesses
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Field Characteristics
Field Name Uniquely Identifies Each Field
Data Type
Text
Numeric
Autonumber
Currency
Date
Memo
Hyperlink
Object
Field Size
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Record
Group of Related Fields
Key Field
AKA Primary Key
Uniquely Identifies Each Record
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Table / File
Collection of Related Records Stored on Disk
Each Record in File Contains Same Fields
Each Field Contains Different Data
Database Composed of Group of Related Tables /
Files
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Popular DBMS
Database
Manufacturer
Computer Type
Access
Microsoft Corporation
PC, server, PDA
DB2
IBM Corporation
PC, midrange server, mainframe
Informix
IBM Corporation
PC, midrange server, mainframe
Ingres
Computer Associates
International, Inc.
PC, midrange server, mainframe
Oracle
Oracle Corporation
PC, midrange server, mainframe, PDA
SQL Server
Microsoft Corporation
Server
Sybase
Sybase Inc.
PC, midrange server, PDA
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File Maintenance
Procedure That Keeps Data Current
Add Records
Change Records
When You Obtain New Data
Correct Inaccurate Data
Update Existing Data
Delete Records
Record No Longer Needed
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Validation
Process of Comparing Data with a Set of Rules
Find Out if Data is Correct
Reduce Data Entry Errors
Enhance Data Integrity
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Validation
Types
Alpha / Numeric
Correct Data Type Entered
Range
Number is in Specified Range
Completeness
Required Field Contains Data
Consistency
Check Digit
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Data Dictionary
Contains Data About Each File in Database
Contains Data About Each Field in Those Files
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Form
On Screen Window
Provides Areas for Entering / Changing Data in a Single
Record
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Report Generator
Generates Report Without User’s Knowledge of
Programming
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Report Types
Detailed
Summary
Consolidates Data
Exception
Identifies Data Outside of Norm
Conditions Define Status Range
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Query
Request Specific Data from Database
SQL (Structured Query Language)
Allow Users to Specify Data to Display, Print, or Store
QBE (Query By Example)
Retrieves Records that Match Criteria Entered in Form Fields
QBE
Criteria
Result
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File Processing System
Each Department Has Own Set of Files
Records in One File May Not Relate to Records in
Other Files
Weakness
Redundancy
Same Fields Stored in Multiple Files
Isolated
Difficult to Access
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Database System
Many Programs & Users Can Share Data
Secures Data
Only Authorized Users Can Access Certain Data
Can View Data But Not Update or Change It
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Storage Differences
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Database System Strengths
Reduced Redundancy
Improved Integrity
Shared Data
Easier Access
Reduced Development Time
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Data Model
How Database Organizes Data
Defines How Users View Data
Types
Relational
Object-oriented
Multidimensional
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Relational Database
Stores Data in Tables
Consist of Rows & Columns
Each Row has Primary Key
Related Tables Must Have
a Common Field
row
column
table
relationships
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Object-oriented Database (OODB)
Stores Data in Objects
Advantages
Can Contain Both Data & Activities That Read / Process Data
Can Store More Types of Data
Can Access Data Faster
Example
Multimedia Database
Store Images, Audio, and/or Video
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Multidimensional Database
Stores Data in Dimensions
Multiple Dimensions Allow Users to Analyze Any View of
Data
AKA Hypercube
Advantages
Consolidates Data Much Faster than Relational Database
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Multidimensional Database
Data Warehouse
From Multiple Databases
Comprehensive Data
Required to Analyze Data Across Enterprise
Examples
Data Mining
Process of Finding Patterns & Relationships Among Data
Click Stream
Collection of Every Action Users Makes in Web Site
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Database Development Guidelines
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