Data Management: Chapter 16 exercises

2.

Surf the Web to find examples of each of the seven universal models of information organization. Which model appears to be most commonly used?

The most commonly used model is a hierarchical basic structure with a mix of various other structures used wherever appropriate.

Examples of the various information organization models can be found at:

Structure	URL
Linear	The CNN news summary at http://cnn.com/QUICKNEWS/ is a good example of the use of a linear information organization model. Here various news stories can be found on the same page. It is intended for the reader to scan or read from top to bottom to get at a quick glance at latest news.
Hierarchical	At http://www.sentrytech.com/smhome.htm one can find the home page of Software, a magazine. The page gives the content of the current issue (title and abstract of the articles). From here one can click on the article and find a full-text version. At the end of each article there are links to some "side bars" digging even deeper into the same topic.
Web	At http://www.cnn.com/ one can find a good example of the use of a Web information organization model. Here the reader is presented with the main news story of the day and then has various alternatives from which to choose. Some of the stories included in the general news page may also be included in the "World" or another news selection. Also when opening a specific story, all links to related current and old articles will be provided. Thus, readers can move through the pages depending on their particular information needs.
Parallel	The answer to the request for a Delta flight schedule on a specific date between two airports is presented using a parallel information organization model at http://www.delta-air.com/trip_a2z/sched/index.html
Matrix	The 1997 annual report of Philips in the Netherlands shows the financial information in the usual matrix (table) format at http://www.philips.com/finance/results/AR97/main_fig/balance.htm.
Overlay	This applet shows the current location of navigation satellites superimposed on an earth projection. http://satnav.atc.ll.mit.edu/java/SVOverlay/SVOverlay.shtml.
Spatial zoom	Delta uses the spatial zoom information organization model when showing all its world wide destinations at http://www.delta-air.com/trip_a2z/destin/index.html. The visitor can click on a region of the world, which is then "enlarged" and all destination in that region are shown. A more traditional use of spatial zoom can be found on the lung anatomy page of the Department of Radiology at The University of Iowa College of Medicine, Iowa City, IA at http://vh.radiology.uiowa.edu/Providers/Textbooks/LungAnatomy/LungAnatomy.html. Here small thumbnail images are inserted into the text. They can be enlarged as needed by the reader.

5.

What are the advantages and disadvantages of PHP?

Advantages	Disadvantages
A free open source server-scripting language	A weakly typed language
Short learning curve	Poor OO support
Quick development time
Good performance
Specifically designed for Web development
Supports all major operating systems
Well-integrated with most DBMSs

7.

What are the differences between Java and JavaScript?

JavaScript	Java
Interpreted (not compiled) by client.	Compiled on server before execution on client.
Object-based. Code uses built-in, extensible objects, but no classes or inheritance.	Object-oriented. Applets consist of object classes with inheritance.
Code integrated with, and embedded in, HTML.	Applets distinct from HTML (accessed from HTML pages).
Variable data types not declared (loose typing).	Variable data types must be declared (strong typing).
Dynamic binding. Object references checked at run-time.	Static binding. Object references must exist at compile-time.
Secure. Cannot write to hard disk.	Secure. Cannot write to hard disk.

Chapter 16

Answers to exercises