Professor Michael J. LosaccoCIS 1110 – Using Computers

Database ManagementChapter 9

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Overview

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

DBMS (Database Management System)

Organized Collection of DataFor 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

Processed Data Becomes Information

Largest Commercial Database

2 PB — Yahoo (Oracle on Unix 2010)

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Data & Information

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

Database Contains TablesTable Contains RecordsRecord Contains FieldsField Contains Characters

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Database Hierarchy

FieldCombination of One or More Characters

Smallest Unit of Data User Accesses

CharacteristicsName Uniquely Identifies Each Field

Data TypeText

Numeric

Currency

Size

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Database Hierarchy

Record

Group of Related Fields

Key Field

AKA Primary Key

Uniquely Identifies Each Record

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Database Hierarchy

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

File MaintenanceProcedure That Keeps Data Current

Add RecordsWhen You Obtain New Data

Change RecordsCorrect Inaccurate Data

Update Existing Data

Delete RecordsRecord No Longer Needed

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Maintaining Data

ValidationComparing Data with Set of Rules

Reduce Data Entry Errors

Enhance Data Integrity

Types

Alpha / Numeric

Range

Completeness

Consistency

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Features

Data DictionaryLists Fields For Each Table in Database

Lists Properties For Each Field in Table

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Features

Form

On Screen Window

View Single Record

Area to Enter / View / Change Data

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Features

Report Generator

Creates Report

Without User’s Knowledge of Programming

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Features

Report Types

Detailed

Summary

Consolidates Data

Exception

Identifies Data Outside of Norm

Conditions Define Status Range

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Features

QueryRequest 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

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

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

Log Example

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Database Models

Model

Rules & Standards Defining:

How Database Organizes Data

How Users View Data

Types

Relational

Object-oriented

Multidimensional

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Database Models

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

Relational

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Database Models

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

Object-Oriented ExamplesMultimedia

Images, Audio Clips, Video Clips

CADEngineering, Architectural, Scientific Data

GroupwareSchedules, Calendars, Memos, Reports

HypertextLinks to Other Documents

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Database Models

Object-Oriented Example

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Database Models

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

Multidimensional Examples

Data Warehouse

Comprehensive Data

Required to Analyze Data Across Enterprise

From Multiple Databases

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Database Models

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

Process