introduction to db and dbms

Introduction to Database and

Database Management Systems

Discovering Computers Fundamentals, 2010 Edition

Chapter 91

Objectives Overview

Define the term, database, and explain how a database interacts with

data and information

Describe the qualities of valuable information

Discuss the terms character, field, record,

and filedata and information

Describe file maintenance techniques (adding records, modifying

records, deleting records) and validation techniques

Differentiate between a file processing approach

and the database approach


Chapter 92See Page 351

for Detailed Objectives

Objectives Overview

Discuss the functions common to most

database management systems

Describe characteristics of relational, object-

oriented, and multidimensional

databasesdatabases

Explain how to access Web databases

Discuss the responsibilities of

database analysts and administrators


Chapter 93See Page 351

for Detailed Objectives

Databases, Data, and Information

Database

• Collection of data organized in a manner

Data

• Collection of unprocessed items

Information

• Processed data

• Documentsin a manner that allows access, retrieval, and use of that data

items

• Text

• Numbers

• Images

• Audio

• Video

• Audio

• Images

• Video


Chapter 94Page 352



Chapter 95Pages 352 – 353

Figure 9-1


• Database software, often called a database

management system (DBMS), allows users to:

Create a computerized Add, modify, and


Chapter 9652

Create a computerized database

Add, modify, and delete data

Sort and retrieve dataCreate forms and

reports from the data


• Data integrity identifies the quality of the data

• Garbage in, garbage out (GIGO) points out the

accuracy of a computer’s output depends on the

accuracy of the inputaccuracy of the input


Chapter 97Page 353


• Valuable information should have the following

characteristics:


Chapter 98Page 354

AccurateAccurate VerifiableVerifiable TimelyTimely OrganizedOrganized

AccessibleAccessible UsefulUsefulCost-

effectiveCost-

effective

The Hierarchy of Data

• Data is organized in layers

– Files, records, fields, characters


Chapter 99Page 355

Figure 9-2


• A character is one byte

– Numbers, letters, space,

punctuation marks, or

other symbols

• A field is a combination • A field is a combination

of one or more related

characters

– Field name

– Field size

– Data type


Chapter 910Pages 355 – 356

Figure 9-3


• Common data types include:

Text Numeric AutoNumber Currency


Chapter 911Page 356

Date Memo Yes/No Hyperlink

Object Attachment


• A record is a group of related fields

– A primary key uniquely identifies each record

• A data file is a collection of related records


Chapter 912Page 356

Figure 9-4

Maintaining Data

• File maintenance refers to the procedures that

keep data current

Adding Modifying


Chapter 913Pages 357 - 358

Adding records

Modifying records

Deleting records

Maintaining Data

• Users add new records to a file when they obtain

new data


Chapter 914Page 357

Figure 9-5

Maintaining Data

• Users modify a record to correct inaccurate data

or update old data



Figure 9-6

Maintaining Data

• When a record no longer is needed, a user deletes

it from a file



Figure 10-7

Maintaining Data

• Validation compares data with a set of rules or

values to find out if the data is correct

Alphabetic/Numeric Check

Range check Consistency check



CheckRange check Consistency check

Completeness check Check digit Other checks

Click to view Web Link,click Chapter 9, Click Web Link from left navigation, then click Data Validationbelow Chapter 9

File Processing Versus Databases

File processing system

• Each department has its own set of files

• Used for many years

• Each department has its own set of files


Database approach

• Programs and users share data

• Reduce data redundancy

• Programs and users share data





• Have data redundancy

• Isolate data


• Have data redundancy

• Isolate data


• Improve data integrity

• Share data

• Allows easier access

• Reduces development time

• Can be more vulnerable


• Improve data integrity

• Share data

• Allows easier access

• Reduces development time

• Can be more vulnerable

File Processing Versus Databases


Chapter 919Page 362

Figure 9-10



Chapter 920Page 363

Figure 9-11

Click to view Web Link,click Chapter 9, Click Web Link from left navigation, then click MySQLbelow Chapter 9


• A data dictionary contains data about each file in

the database and each field in those files


Chapter 921Page 364

Figure 9-12


• A DBMS provides several tools that allow users

and programs to retrieve and maintain data in the

database Query languageQuery language



Query by exampleQuery by example

FormForm

Report generatorReport generator


• A query language consists of simple, English-like

statements that allow users to specify the data to

display, print, or store

• Query by example (QBE) provides a GUI to assist • Query by example (QBE) provides a GUI to assist

users with retrieving data





Chapter 924Page 365

Figure 9-13


• A form is a window on the screen that provides

areas for entering or modifying data in a database


Chapter 925Page 366


• A report generator allows users to design a report

on the screen, retrieve data into the report

design, and then display or print the report


Chapter 926Page 366

Figure 9-15


A DBMS provides means to ensure that only authorized users access data at permitted timesdata at permitted times

• Access privileges

• Principle of least privilege


Chapter 927Page 367

Click to view Web Link,click Chapter 9, Click Web Link from left navigation, then click Data Securitybelow Chapter 9


• A DMBS provides a variety of techniques to

restore the database to a usable form in case it is

damaged or destroyed


Chapter 928Page 367

BackupBackup LogLog

Recovery

utility

Recovery

utility

Continuous

backup

Continuous

backupClick to view Web Link,click Chapter 9, Click Web Link from left navigation, then click Continuous Backup below Chapter 9

Relational, Object-Oriented, and

Multidimensional Databases

• A data model consists of rules and standards that define how the database organizes data

• A relational databasestores data in tables that


Chapter 929Page 368

Figure 9-17

stores data in tables that consist of rows and columns– Each row has a primary key

– Each column has a unique name

• A relationship is a link within the dataClick to view Web Link,

click Chapter 9, Click Web Link from left navigation, then click Relational Databases below Chapter 9



• Structured Query Language (SQL) is a query

language that allows users to manage, update,

and retrieve data


Chapter 930Page 369

Figure 9-18



• An object-oriented database (OODB) stores data

in objects

• Object-oriented databases often use Object

Query Language (OQL) to manipulate and retrieve Query Language (OQL) to manipulate and retrieve

data


Chapter 931Page 369

Click to view Web Link,click Chapter 9, Click Web Link from left navigation, then click Object-Oriented Databases below Chapter 9



• A multidimensional database can store data in more

than two dimensions of data

– Sometimes known as a hypercube

– Can consolidate data much faster than a relational database

• A data warehouse is a huge database that stores and

manages the data required to analyze historical and

current transactions


Chapter 932Page 370

Click to view Web Link,click Chapter 9, Click Web Link from left navigation, then click Data Warehousesbelow Chapter 9

Web Databases

• Databases on the Web allow you to:

Shop for products or

servicesBuy or sell stocks Search for a job



products or services

Buy or sell stocks Search for a job

Make airline reservations

Register for college classes

Check semester grades

Web Databases


Chapter 934Page 371

Figure 9-19

Database Administration

• It is important to have a carefully designed

database


Chapter 935Page 371

Figure 9-20

Click to view Web Link,click Chapter 9, Click Web Link from left navigation, then click Database Design Guidelines below Chapter 9


Database analysts and administrators are responsible for managing and coordinating all database activitiesDatabase analysts and administrators are responsible for managing and coordinating all database activities

Database Analyst (DA)Database Administrator (DBA)

Creates and maintains the data Decides on proper field placement, defines data

relationship, and identifies users’ access privileges

Creates and maintains the data dictionary, manages security, monitors performance, and checks backup and recovery

procedures


Chapter 936Page 371


• Employees should learn

how to use the data in

the database effectively

– Interact with database

– Identify new data for the

database

– Maintain the database


Chapter 937Page 372

Summary

How data and information are

valuable assets to an organization

Methods for maintaining high-

quality data

Assessing the quality of valuable

informationan organization

quality data information

Advantages of organizing data in

a database

Various types of databases

Roles of the database analysts

and administrators


Chapter 938Page 372

introduction to db and dbms

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