Download 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



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

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Accurate
Verifiable
Timely
Organized
Accessible
Useful
Cost-effective
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Data Hierarchy


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Database Contains Files
File Contains Records
Record Contains Fields
Field Contains Characters
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Field
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Combination of One or More Characters

Smallest Unit of Data User Accesses
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Field Characteristics
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Field Name Uniquely Identifies Each Field
Data Type

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
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

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
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
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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
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Generates Report Without User’s Knowledge of
Programming
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Report Types

Detailed

Summary


Consolidates Data
Exception

Identifies Data Outside of Norm
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Conditions Define Status Range
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Query
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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

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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
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Many Programs & Users Can Share Data
Secures Data
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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
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Improved Integrity

Shared Data

Easier Access

Reduced Development Time
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Data Model
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How Database Organizes Data

Defines How Users View Data
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Types
 Relational
 Object-oriented
 Multidimensional
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Relational Database
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Stores Data in Tables
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Consist of Rows & Columns
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Each Row has Primary Key
Related Tables Must Have
a Common Field
row
column
table
relationships
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Object-oriented Database (OODB)
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Stores Data in Objects

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Advantages

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
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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