1. Using Information Technology
Chapter 8
Files, Databases, & E-Commerce
To the instructor:
This presentation attempts to cover every term in the text, sometimes via a slide, sometimes via the Notes page.
Additional material beyond what is in the text is presented via:
Occasional “FACTOID” notations on the Notes page, and;
Occasional hyperlinks in the slides themselves. ScreenTip text has been added to each hyperlink allowing you to see in advance of selecting the hyperlink where that link will take you.
In addition, the last ~20 slides are questions covering the material just presented. They can be used to increase interaction between the instructor and students at the end of each lecture, to ensure students understand the material just presented, etc.
Finally, some of the Notes pages include “Discussion questions” for use in encouraging student interaction during the lecture.

2. Files, Databases, & E-Commerce Digital Engines for the New Economy
8.1 Managing Files: Basic Concepts
8.2 Database Management Systems
8.3 Database Models
8.4 Features of a Database Management System
8.5 Databases & the New Economy: E-Commerce, Data Mining, & B2B Systems
8.6 The Ethics of Using Databases: Concerns about Accuracy & Privacy
Key Questions (from the text):
8.1 Managing Files: Basic Concepts. What are the data storage hierarchy, the key field, types of files, sequential versus direct access, and offline versus online storage?
8.2 Database Management Systems. What are the benefits of database management systems, and what are four types of database access?
8.3 Database Models. What are four types of database models?
8.4 Features of a Database Management System. What are the features of a database management system?
8.5 Databases & the New Economy: E-Commerce, Data Mining, & B2B Systems. How are e-commerce, data mining, and business-to-business systems using databases?
8.6 The Ethics of Using Databases: Concerns about Accuracy & Privacy. What are some ethical concerns about the uses of databases?
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3. 8.1 Managing Files: Basic Concepts
Data storage hierarchy - levels of data stored in a computer:
Database
Files
Records
Fields
Characters (bytes)
Bits
Database - an organized collection of integrated files.
File - a collection of related records.
Record - a collection of related fields.
Field - a unit of data consisting of one or more characters (bytes).
Character (byte) - a letter, number, or special character.
Key field - a field that is chosen to uniquely identify a record so that it can be easily retrieved and processed.
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Types of Files
Filename - name given to a file
Extension - three letters following a period in a filename
Program files - files containing software instructions
Data files - files that contain data (words, numbers, pictures, sounds, etc.)
Source program file - one that contains high-level computer instructions in the original form written by the programmer.
.bas for BASIC
.jav for Java
Executable file - one that contains the instructions that tell the computer how to perform a particular task.
.exe
.dll
.drv
Data file extension examples:
.ppt for PowerPoint
.doc for Word
.mdb for Access
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Types of Files
ASCII files
Image (graphic) files
Audio files
Animation/video files
Web files
ASCII files are text-only and may use the .txt extension.
Image filename extension examples: .bmp, .gif, .jpg
Audio filename extension examples: .wav and .mid
Animation/video filename extension examples: .avi, .flc, .fli, .mpg
Web filename extension examples: .html, .htm, .xml
Discussion question: Who has a short name? Let’s use the ASCII chart (link above) to spell out that name in binary. (Don’t forget the spaces between first and last names.)
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Two Types of Data Files
Master file -
a data file containing relatively permanent records that are generally updated periodically
Transaction file -
a temporary holding file that holds all changes to be made to the master file: additions, deletions, revisions
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Data Access Methods
Sequential storage -
data is stored and retrieved in sequence
Direct access storage -
the computer can go directly to the information you want
Sequential storage example: tape storage.
Direct access storage example: hard disks and other types of disks.
FACTOID: IBM came up with the acronym DASD for “Direct Access Storage Device.” Pronounced “daz-dee,” this term has come into fairly wide acceptance in the mainframe world.
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8. Offline versus Online Storage
Offline storage -
data is not directly accessible for processing until the tape or disk it’s on has been loaded onto an input device
Online storage -
stored data is randomly (directly) accessible for processing
FACTOID: In addition to online storage and offline storage, more recently the term “near line storage” has come into existence. Like online storage, near line storage is directly accessible by the CPU. But like offline storage, users may have to wait awhile before their request for data is fulfilled.
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9. 8.2 Database Management Systems
Database management system (DBMS) - programs that control the structure of a database and access to the data
Advantages of DBMSes:
File sharing
Reduced data redundancy
Improved data integrity
Increased security
Data redundancy - situation in which the same data fields appear in many different files and often in different formats.
Data integrity - measure of how accurate, consistent, and up-to-date data is.
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10. Four Types of Database Access
Individual database - collection of integrated files used by one person
Shared database - database shared by users in one company or organization in one location
Distributed database - stored on different computers in different locations and connected by a client/server network
Public databank - compilation of data that is available to the public
Database administrator (DBA) - person who coordinates all related activities and needs for an organization’s database, whether shared, distributed, or public.
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8.3 Database Models
Hierarchical database - fields or records are arranged in related groups, resembling a family tree, with child (lower-level) records subordinate to parent (higher-level) records
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Database Models
Network database - similar to a hierarchical database, but each child record can have more than one parent record
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Database Models
Relational database - a database which relates (connects) data in different files through the use of a key field, or common data element
SQL (Structured Query Language) - the standard language used to create, modify, maintain, and query relational databases.
FACTOID: SQL is pronounced as “sequel.” How did this acronym get such an unlikely pronunciation? The first structured query language was developed by IBM in the 1970s; its product name was “Sequel2.”
QBE (Query by example) - feature of most query languages in which the user asks for information in a database by using a sample record to define the qualifications he or she wants for selected records.
FACTOID: E. F. Codd is considered the “father” of relational database management systems—the most common model of databases. His article entitled “A Relational Model of Data for Large Shared Data Banks” was published in the June 1970 “Communications of the ACM.”
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Database Models
Object-oriented database - database which uses “objects”--software written in small, reusable chunks--as elements within database files
An object consists of:
Data in any form, and
Instructions on the actions to take on the data
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15. 8.4 Features of a Database Management System
Data dictionary - a procedures document or disk file that stores the data definitions or a description of the structure of data used in the database
DBMS utilities - programs that allow you to maintain the database
Report generator - program for producing an onscreen or printed document from all or part of a database
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16. Features of a Database Management System
Access security - a feature allowing DBAs to specify different access privileges for different users
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17. Features of a Database Management System
System recovery - features that allow a DBA to recover contents of the database in the event of a hardware or software failure
Four approaches to system recovery:
Mirroring
Reprocessing
Rollforward
Rollback
Mirroring - two copies in different locations.
Reprocessing - redoing the processing from a known past point.
Rollforward - a more sophisticated version of reprocessing, in which the lost data is recovered using a transaction log.
Rollback - undoing unwanted changes.
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8.5 Databases & the New Economy: E-Commerce, Data Mining, & B2B Systems
E-commerce (electronic commerce) - the buying and selling of products and services through computer networks
Discussion question:
What is your favorite e-commerce site? Why do you like it? (Then visit each site mentioned.)
FACTOID: One of many industries that have sprung into existence in just the past few years is e-commerce review sites. BizRate, one of the oldest and best known of these sites, has as its mission “to empower online shoppers with more choice, confidence and convenience as Earth's best marketplace. “
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Data Mining
Data mining (DM) - the computer-assisted process of sifting through and analyzing vast amounts of data in order to extract meaning and discover new knowledge
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Data Mining
Data sources:
Point-of-sale transactions in flat files on mainframes;
Databases of all kinds;
Other--news articles, online articles, etc.; and
Data from data warehouses.
Data fusion and cleansing
Data and meta-data
Data warehouse
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Data Mining
Data sources
Data fusion and cleansing - putting together the data from various sources and then “scrubbing” the data to eliminate errors and inconsistencies
Data and meta-data
Data warehouse
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Data Mining
Data sources
Data fusion and cleansing
Data and meta-data - cleaned-up data and meta-data (data about data)
Data warehouse
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Data Mining
Data sources
Data fusion and cleansing
Data and meta-data
Data warehouse - a special database of cleaned up data and meta-data
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Data Mining
Three kinds of software, or “siftware” tools used to perform data mining finding and analyzing tasks:
Query-and-reporting tools
Multidimensional-analysis tools
Intelligent agents
Query-and-reporting tools - best used for specific questions to verify hypotheses; require a database structure.
MDA tools - can do “data surfing” to explore all dimensions of a particular subset of data.
Intelligent agents - computer programs that roam through networks performing complex work tasks for people.
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25. Business-to-Business (B2B) Systems
B2B - a system in which a business sells to other businesses, using the Internet or a private network to cut transaction costs and increase efficiencies
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26. 8.6 Ethics of Using Databases: Concerns about Accuracy & Privacy
Morphing - process in which a film or video is displayed on a computer screen and altered pixel by pixel, or dot by dot, into something else
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27. The Ethics of Using Databases
Manipulation of video & television
Manipulation of photos
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28. The Ethics of Using Databases
Privacy - the right of people not to reveal information about themselves
Graphic depicts a wallet-size card which can contain 2000 pages of a patient’s medical history. Privacy advocates worry that the ability to concentrate info in databases and smart cards may mean that the records cannot be kept private.
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29. The Ethics of Using Databases
Manipulation of sound
Monopolizing information
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Concept Check
What employee coordinates all related activities and needs for an organization’s database?
Database administrator (DBA)
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Concept Check
What file stores data definitions and descriptions of database structure?
Data dictionary
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Concept Check
What type of storage allows the computer to go directly to the information you want?
Direct access storage
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Concept Check
What is the term for the same data fields appearing in many different files, and often in different formats?
Data redundancy
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Concept Check
What is the term for the measure of data’s accuracy, consistency, and up-to-date status?
Data integrity
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Concept Check
What type of database is stored on different computers in different locations connected by a client/server network?
Distributed database
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Concept Check
What model of database has fields or records arranged in related groups resembling a family tree, with child (lower-level) records subordinate to parent (higher-level) records?
Hierarchical database
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Concept Check
What is the standard language used to create, modify, maintain, and query relational databases?
SQL (Structured Query Language)
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Concept Check
Which approach to database system recovery involves maintaining two copies in different locations?
Mirroring
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Concept Check
What is the term for data about data?
Meta-data
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Concept Check
What is the process whereby a film or video image is displayed on a computer screen and altered pixel by pixel, or dot by dot, until the image metamorphoses into something else?
Morphing
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Concept Check
Which model of database connects data in different files through the use of a key field?
Relational database
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Concept Check
What are the levels of data in the data storage hierarchy, from smallest to largest?
Bits, bytes (characters), fields, records, files, databases
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Concept Check
What is the name for the three characters appearing after a period at the end of a filename?
Extension
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Concept Check
What is the most important advantage of databases?
File sharing
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Concept Check
Which approach to database system recovery involves undoing unwanted changes?
Rollback
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Concept Check
What is a special database of cleaned up data and meta-data called?
Data warehouse
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Concept Check
What is the term for a system in which a business sells to other businesses using the Internet or a private network to cut transaction costs and increase efficiencies?
B2B (Business-to-business) system
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Concept Check
What kind of file contains high-level computer instructions in the original form written by the programmer?
Source program file
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Concept Check
What model of database is similar to a hierarchical database, but each child record can have more than one parent record?
Network database
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