Transcript The World Wide Web

Information
and
Databases
©1999 Addison Wesley Longman
4
Slide 4.1
Table 4.1
Using a CAD System to Design the Boeing 777
©1999 Addison Wesley Longman
Slide 4.2
Table 4.1
Using a CAD System to Design the Boeing 777
CUSTOMER
Boeing’s manufacturing department
Airline maintenance departments
©1999 Addison Wesley Longman
Slide 4.3
Table 4.1
Using a CAD System to Design the Boeing 777
PRODUCT
Specification of the precise function, shape, and location of
each component
Verification that the components are physically compatible
©1999 Addison Wesley Longman
Slide 4.4
Table 4.1
Using a CAD System to Design the Boeing 777
BUSINESS PROCESS
Major Steps:
•Decide on major features of airplane
•Design individual components
•Test for compatibility with other components and other subsystems
•Transmit the specifications to manufacturing
Rationale:
•Use a paperless design process to avoid delays related to copying
and moving paper, and to use the design data directly to test for
interference between components.
©1999 Addison Wesley Longman
Slide 4.5
Table 4.1
Using a CAD System to Design the Boeing 777
PARTICIPANTS
INFORMATION
TECHNOLOGY
Representatives of airlines
General design goals
Boeing engineers
CAD specification of the
shape, location,
materials, and function
of each component
CAD database and computer
for storing the data
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Terminals and data network
Slide 4.6
Figure 4.1
Entity-relationship diagram for part of a university registration system
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Slide 4.7
Figure 4.2
Types of relationships in entity-relationship
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Slide 4.8
Table 4.2
Possible Attributes for the Entity Types in Figure 4.1
DEPARTMENT
PROFESSOR
•Department identifier
•College
•Department head
•Scheduling coordinator
•Employee identification number
•Name
•Address
•Birthdate
•Office telephone
•Social Security number
COURSE
•Course number
•Department
•Required of department major (y/n)
•Course description
SECTION
•Section identification number
•Semester
•Year
•Classroom
•Start time
•End time
•Days of week for class meetings
STUDENT
•Student identification number
•Name
•Address
•Birthdate
•Telephone
•Gender
•Ethic group
•Social Security number
OFFICE
•Office number
•Building
•Telephone extension
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Slide 4.9
Figure 4.3
Images produced by information systems
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Slide 4.10
Table 4.3
Excerpt from a Hypothetical Student File
Social security number: 044-34-5542
Last name: Bates
First name: Alvin
Street address: 243 Third Street
City: Middleton
State: MA
Zip code: 02137
Date of birth: 05/07/78
©1999 Addison Wesley Longman
Slide 4.11
Figure 4.4
Entity-relationship diagram from a relational database
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Slide 4.12
Figure 4.5
Posing a query in Microsoft Access
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Slide 4.13
Figure 4.6
Using a natural language query
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Slide 4.14
Figure 4.7
A Multidimensional database
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Slide 4.15
Figure 4.8
Using a geographical information system
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Slide 4.16
Figure 4.9
Use of schemas and subschemas
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Slide 4.17
Figure 4.10
Locating data using direct access
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Slide 4.18
Figure 4.11
Locating data using indexes
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Slide 4.19
Figure 4.12
Backup and recovery
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Slide 4.20
Figure 4.13
Retrieving a Web page
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Slide 4.21
Table 4.4
Differences between Using a Relational Database and Using the World Wide Web
BASIC STRUCTURAL ELEMENTS
Traditional database: Tables, records, fields, keys
The World Wide Web: Web pages and hyperlinks
BASIC ORGANIZING PRINCIPLE
Traditional database: Predefined tables and relationships that have a specific meaning in a specific
business context
The World Wide Web: Author-defined links from any location in a Web page to any other location on
the same Web page or to another Web page
FINDING SPECIFIC INFORMATION
Traditional database: Identify specific records or fields in those records and the DBMS will find them
The World Wide Web: Identify a specific Web address (URL) and the browser will find and display
the page if it is available
FINDING INFORMATION RELATED TO THE INFORMATION MOST RECENTLY ACCESSED
Traditional database : No typical method
The World Wide Web : Click on a hypertext link
METHOD FOR IDENTIFYING DATA REQUIRED IN A QUERY
Traditional database: State selection criteria in terms of specific values of specific data items in
specific tables
The World Wide Web: Identify words or terms that should appear in the Web pages selected by the
search engine
©1999 Addison Wesley Longman
Slide 4.22
Table 4.4
Differences between Using a Relational Database and Using the World Wide Web
HOW THE COMPUTER FINDS THE DATA BY SEARCHING
Traditional database: DBMS finds the pertinent tables in the database and selects the
appropriate data from the records that meet the criteria
The World Wide Web: Search engine finds every Web page containing each word or
phrase in the query, then prioritizes these based on the priorities in the query
TREATMENT OF IMPOSSIBLE OR RIDICULOUS QUERIES
Traditional database: DBMS rejects queries not phrased in terms of tables, fields, and
relationships in the database
The World Wide Web: The search engine performs whatever search is requested
LIKELIHOOD THAT A QUERY WILL PRODUCE USABLE RESULTS
Traditional database: DBMS returns exactly what is requested; if the user asks the
wrong question, the result may not be useful
The World Wide Web: Many of the Web pages found by a search engine may be
unrelated to what the user wanted
METHODS FOR CONTROLLING DATA QUALITY
Traditional database: During data entry DBMS checks for obvious errors such as
missing values, out-of-range values, etc.
The World Wide Web: The Web has no organized method of controlling quality of
information in Web pages
©1999 Addison Wesley Longman
Slide 4.23
Table 4.5
Determinants of Information Usefulness and Related Roles of Information Syatems
INFORMATION QUALITY
•ACCURACY
•PRECISION
•COMPLETENESS
•AGE
•TIMELINESS
•SOURCE
©1999 Addison Wesley Longman
Slide 4.24
Table 4.5
Determinants of Information Usefulness and Related Roles of Information Systems
INFORMATION ACCESSIBILITY
•AVAILABILITY
•ADMISSIBILITY
INFORMATION PRESENTATION
•LEVEL OF SUMMARIZATION
•FORMAT
INFORMATION SECURITY
•ACCESS RESTRICTION
•ENCRYPTION
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Slide 4.25
Figure 4.16
Do managers expect the truth?
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Slide 4.26
Fig 4.17
Diagram representing a mental model
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Slide 4.27
Figure 4.18
A virtual reality simulation
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Slide 4.28