McGraw-Hill 8-1 © 2011 The McGraw-Hill Companies, Inc. All rights reserved.

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© 2011 The McGraw-Hill Companies, Inc. All rights reserved.

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Databases & Information Systems

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8.1 Managing Files: Basic Concepts

A database is a logically organized collection of related data designed and built for a specific purpose

Data is stored hierarchically for easier storage and retrieval

Files: collections of related records Records: collections of related fields

Field: unit of data containing 1 or more characters Character: a letter number or special character made of bits

Bit: a 0 or 1


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Key Field – the field that uniquely identifies a record Often an identifying number, such as social security

number or a student ID number Keys are used to sort records in different ways Primary keys must be unique

Keys are used to access particular records in a database Unique keys make records distinguishable from one

another Foreign keys appear in other tables and usually refer to

primary keys in particular tables; they are used to relate one table to another (to cross-reference data)


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Program files and Data Files Program files are files containing software instructions

Source program files are written by the software developer in the programming language Double-clicking on them won’t run them They have such file extensions as .cpp, .jav, .bas

Executable files are program files translated so they can be executed on the computer Double-clicking on them will usually cause them to run They have such file extensions as .exe and .com

Data files are files that contain--words, numbers, pictures, sounds. etc.


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Data files are the files used in databases, spreadsheets, and word-processing documents

Data files have filenames and such extensions as .txt (text), .mdb (Acess), .ppt (Powerpoint), and .xls (Excel)

Graphics files have such extensions as .tiff, .jpeg, and .png Audio files have such extensions as .mp3, .wav, and .mid Animation/video files have such extensions as .qt, .mpg, .avi,

and .rm Data files are often compressed to save space and

transmit them faster Compression removes repetitive elements from a file


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8.2 Database Management Systems

Database Management System (DBMS) Software written specifically to control the structure of a

database and access to the data DBMS benefits:

Reduced data redundancy (redundant data is stored in multiple places, which causes problems keeping all the copies current)

Improved data integrity--means the data is accurate, consistent, and up to date

Increased security—DBMS limits who can create, read, update, and delete the data

Ease of data maintenance—DBMS offers validation checks, backup utilities, and standard procedures for data inserting, updating, and deletion


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3 Principal Database Components Data Dictionary

Repository that stores the data definitions and descriptions of the structure of the data and the database

DBMS Utilities Programs that allow you to maintain the database by

creating, editing, deleting data, records, and files Also include automated backup and recovery

Report Generator Program for producing on-screen or printed readable

documents from all or part of a database


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Database Administrator (DBA) Coordinates all related activities and needs for an

organization’s database Ensures the database’s:

Recoverability Integrity Security Availability Reliability Performance


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8.3 Database Models

Database Type Description

Hierarchical database Fields or records are arranged in a family tree, with child records subordinate to parent or higher-level records

Network database Like a hierarchical database, but each child record can have more than one parent record

Relational database Relates, or connects, data in different files through the use of a key, or common data element

Object-oriented database Uses objects (software written in small, reusable chunks) as elements within database files

Multidimensional database Models data as facts, dimensions, or numerical measures for use in the interactive analysis of large amounts of data


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8.3 Database Models

Hierarchical Database Fields or records are arranged in related groups

resembling a family tree with child (low-level) records subordinate to parent (high-level) records

Root record is the parent record at the top of the database, and data is accessed top-down, through the hierarchy

Oldest and simplest; used in mainframes in 1970s Still used in some reservation systems Is rigid in structure and difficult to update


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8.3 Database Models

Network Database Similar to a hierarchical database but more flexible--

each child record can have more than one parent record Used principally with mainframe computers Requires the database structure to be defined in

advance; flexibility still lacking


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8.3 Database Models

Relational Database Relates or connects data in different files through the use

of a key, or common data element Data stored in tables (relations, or files) of rows (tuples,

or records) and columns (attributes, or fields) More flexible than previous models Examples for large systems are Oracle, Informix, Sybase Examples for microcomputers are Paradox and Microsoft

Access Users don’t need to know data structure to use the

database; primary and foreign keys are used© 2011 The McGraw-Hill Companies, Inc. All rights reserved.

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8.3 Database Models

Relational Database (continued) Users employ SQL (structured query language) to create,

modify, maintain, and query the database Query by Example uses sample record forms to allow users

to define the qualifications for choosing records Some relational database allow the use of natural spoken

language to make queries


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8.3 Database Models


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8.3 Database Models

Object-Oriented Database Uses “objects,” software written in small, manageable

chunks, as elements within data files An object consists of:

Data in any form, including audio, graphics, and video Instructions on the action to be taken with the data This model is a multimedia database

Examples include FastObjects, GemStone, Objectivity DB, Jasmine Object Database, and KE Texpress

Types include web (hypertext) database and hypermedia database, which also includes links


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8.3 Database Models

Multidimensional Database Models data as facts, dimensions, or numerical answers

for use in the interactive analysis of large amounts of data for decision-making purposes

Allows users to ask questions in colloquial language Use OLAP (online analytical processing) software to

provide answers to complex database queries


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8.4 Data Mining

DM is the computer-assisted process of sifting through and analyzing vast amounts of data to extract hidden patterns and meaning and to discover new knowledge

Data is fed into a data warehouse through the following steps: Identify and connect to data sources Perform data fusion and data cleansing Obtain both data and meta-data (data about the data) Transport data and meta-data to the data warehouse

Data warehouse is a special database of cleaned-up data and meta-data


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8.4 Data Mining


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8.4 Data Mining

Methods for searching for patterns in the data and interpreting the results Regression analysis

Develops mathematical formula to fit patterns in the data that has been extracted

Formula is then applied to other data sets of the same type to predict future trends

Classification analysis Statistical pattern-recognition process that is applied to data

sets with more than just numerical data


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8.4 Data Mining

DM applications include: Sports Marketing Health Science Counterterrorism Sentiment analysis Exploring the “deep web”


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8.5 Databases & the Digital Economy

E-Commerce (Electronic Commerce) The buying and selling of products and services through

computer networks Examples of some e-tailers (electronic retailers):

amazon.com sells books and almost everything else sees.com sells candy online priceline.com sells airline tickets and hotel rooms dell.com sells computers and other electronic items


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8.5 Databases & the Digital Economy

Innovative e-tailer technologies make online shopping easier 360-degree images

Allow you to see all sides of an item Order tracking

Bar codes are assigned to items being shipped that allow customers to track shipping progress via the internet

Shop bots Programs that help users search for a particular product or

service and then provide price comparisons


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8.5 Databases & The Digital Economy

Types of E-Commerce Business-to-Business (B2B)

A business sells to other businesses using the internet or a private network to cut transaction costs and increase efficiencies

Business-to-Consumer (B2C) A business sells goods or services directly to consumers

Consumer-to-Consumer (C2C) Consumers sell goods or services directly to other

consumers with the help of a third party, such as eBay; résumé sites are also C2C exchanges, as are dating sites and online communities


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8.6 Using Databases to Help Make Decisions

Information Systems What are the qualities of good information?

Correct and verifiable Complete yet concise Cost effective Current Accessible


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Most organizations have 6 departments within which information must flow: Research and development Production (operations) Marketing and sales Accounting and finance Human resources (personnel) Information systems (IS)

Information flows horizontally between these departments


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Besides the 6 departments, many organizations also have 3 levels of management: Strategic-level management

Top managers (CEOs, COOs, CFOs, CIOs) concerned with long-term, or strategic, planning and decisions

Tactical-level management Middle level managers who make tactical decisions to

implement the strategic goals set for the organization Operational-level management

Low-level supervisors who make daily operational decisions

Information flows vertically through management levels© 2011 The McGraw-Hill Companies, Inc. All rights reserved.

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A Newer Information Flow: Decentralized Organizations The pyramid management structure is flattened

somewhat as employees are given more authority to make day-to-day decisions

Employees increasingly linked to a central database Companies use Groupware CSCW (computer-supported

cooperative work) systems to enable cooperative work by groups of people

Many people can work together from different locations to manage information


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6 computer-based information systems1. Office information systems

2. Transaction processing systems

3. Management information systems

4. Decision support systems

5. Executive support systems

6. Expert systems


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1. Office Information System (OIS) Also called office automation system Combines various technologies to reduce the manual

labor required in operating an efficient office and to increase productivity

Used throughout all levels of an organization Uses, e.g., fax, voice mail, email, scheduling software,

word processing, desktop publishing OIS backbone = network (LAN, intranet, extranet)


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2. Transaction Processing System (TPS) Transactions are recorded events of routine business activities,

such as bills, orders, and inventory TPS systems keep track of the transactions needed to conduct

a business Features of a TPS:

Input and output: transaction data For operational (low-level) managers Produces detail reports (specific information about routine

activities) One TPS for each department Basis for management information systems (MIS) and decision

support systems (DSS)


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3. Management Information System (MIS) Computer-based information system that uses data

recorded by a TPS as input to programs that produce routine reports as output

Features Inputs are processed transaction data; outputs are

summarized, structured reports Designed for tactical (mid-level) managers Draws from all departments Produces several kinds or reports: summary, exception,

periodic, and demand


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4. Decision Support System (DSS) Computer information system that provides a flexible tool

for analysis and helps management focus on the future Features

Inputs are external data and internal data such as summarized reports and processed transaction data; outputs are demand reports from top managers

Assists tactical (mid-level) managers in decision making Produces analytic models

Developed to support the types of decisions faced by managers in specific industries


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5. Executive Support System Easy-to-use DSS made especially for strategic (top-level)

managers to support strategic decision making Uses data from internal systems and data from outside Allows executives to call up predefined reports Includes capability to browse through summarized

information on all aspects of the organization and drill down for detailed data

Allows executives to perform “what-if” scenarios


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6. Expert System Also called knowledge-based system Set of interactive computer programs that helps users to

solve problems that would otherwise require the assistance of a human expert.

Used by both management and nonmanagement personnel to solve specific problems

One of the most useful applications of Artificial Intelligence (AI)


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8.7 Artificial Intelligence

AI is a group of related technologies used to develop software and machines that emulate human qualities such as learning, reasoning, communicating, seeing, and hearing

Areas include: Expert systems Natural language processing Intelligent agents Pattern recognition Fuzzy logic Virtual reality and simulation devices Robotics


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Expert Systems Built by knowledge engineers Include surface knowledge and deep knowledge Three components of an expert system:

Knowledge base: an expert system’s database of knowledge about a particular subject

Inference engine: the software that controls the search of the expert system’s knowledge base and produces conclusions

User interface: the display screen for the user to interact with the expert system


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Natural language processing Allows users to interact with a system using normal language The study of ways for computers to recognize and understand

human language

Intelligent agents A form of software with built-in intelligence that monitors work

patterns, asks questions, and performs work tasks on your behalf; shop bots are intelligent agents

Pattern recognition Involves a camera and software that identify recurring visual

patterns by mapping them against similar patterns stored in a database (e.g., visual surveillance and ID of suspicious people)


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Fuzzy logic A method of dealing with imprecise data and uncertainty,

with problems that have many answers rather than one Has been applied in running elevators to determine

optimum times for elevators to wait; used in many appliances

Virtual reality A computer-generated artificial reality that projects a

person into a sensation of 3-D space Often used as simulators to represent the behavior of

physical or abstract systems—e.g., for pilot training


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Robotics The development and study of machines that can

perform work that is normally done by people Commonly found in manufacturing plants and also in

situations where people would be in danger Nuclear inspections Assembly lines, especially paint lines Checking for land mines and bombs Fighting oil-well fires Mars expedition


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Weak vs. Strong AI Weak AI

Computers can be programmed to simulate human cognition

Strong AI Computers can think on a level that is equal to or better

than humans and can also achieve consciousness


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Strong AI Cyc approach to strong AI

A database in Austin, TX that holds about 1.4 million basic truths

Plan is that Cyc will automatically make human-like assumptions

Hope is that Cyc will learn on its own Cog approach to strong AI

MIT project that is a humanoid robot with sensory systems Tries to identify and search for patterns instead of following

rules and facts


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Turing Test In 1950 Allen Turing predicted computers would

eventually be able to mimic human thinking Turing test determines whether the computer is human

Judge is in another location and doesn’t see the computer Judge converses via a computer terminal with two entities:

one a person and one a computer Judge must determine who is the person and who the

computer If the computer can fool the judge, it is said to be intelligent No computer system has yet passed the Turing test


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Smarter-Than-Human Computers “The Singularity”

A moment when humans would have created self-aware, smarter-than-human machines capable of designing computers and robots that are better than humans can design today

Also may involve transferring the contents of human brains and thought processes into a computing environment


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Ethics in A.I. Computer software is subtly shaped by the ethical

judgments and assumptions of its creators. Will humans lose control of computer systems? There is no such thing as completely value-free

technology.


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8.8 The Ethics of Using Databases

Privacy concerns Privacy is the right of people not to reveal information

about themselves Name migration: your name can migrate to many other

databases—you’ll get endless junk mail and telemarketing calls, and targeted ads online

Résumé rustling and online snooping Government prying and spying

Privacy laws have been enacted, but tension continues between supporters of privacy and supporters of security

Is a national ID card necessary?


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Identity theft concerns Crime in which thieves hijack your identity and use your

good credit rating to get cash, take out loans, order credit cards, and buy things in your name

Read Experience Box on pp. 448 – 449 about dealing with ID theft


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