In this lab exercise, we'll look at some on-line information systems and try to reverse-engineer the database that lies behind them. In particular, we'll try to determine if the system has a database at all, and if so, what the contents and structure of that database are likely to be.

Getting started in the Lab

To do this exercise, you'll have to log into one of the machines in the lab. These machines will have a boot partition for Windows 2003 Server, which we'll use for this course. Start by doing the following:

1. Start/Restart the machine and choose Windows from the boot menu. You will have only a certain amount of time to make your choice.
2. Log into your administrator account - Use the login and password that I give you.
3. Once on, change your password to something you can remember. Do this by hitting Control-Alt-Delete, and selecting "change password".
4. Mark this machine with your name and plan to use it for the remainder of the semester. If you forget your password, we can re-image the machine for you, but that will erase your data and configuration work.

When this is done, familiarized yourself with the environment. Note that you won't have a permanent network drive space here, so you'll have to arrange for your own backups.

Choosing a Website

To start the lab exercise, divide into teams of 2 (or 3) and choose two of the following web sites to analyze (I'll help with your choices here):

• http://www.facebook.com
• http://www.ebay.com
• http://www.amazon.com
• http://www.nytimes.com
• http://news.google.com
• http://www.google.com
• http://www.calvin.edu
• http://cs.calvin.edu
• Knightvision
• http://www.landsend.com
• http://www.pagepan.com
• http://www.dictionary.com
• http://www.dell.com
• Other sites of interest to you?

Discerning the Existence of a Database

Familiarize yourself with the web site and try to determine if it uses a database at all. Almost no web sites are totally database-driven, but are there parts of the site that appear to be database-driven? To help with this, consider the following questions:

• Is it static or dynamic? That is, does it mostly stay the same or does it change over time?
• Is there any information collected that must be persistent (as we discussed in class)?
• Does it offer features that you can't imagine implementing with simple html?
• Does it offer services that the company would want to remember and maintain (e.g., user accounts, purchases, products for sale)?

Reverse-Engineering the Database Structure

Pick one of your sites that does appear to be database-driven and try image what sort of database is driving it. What information must the site store? List the data entities, attributes and relationships that you believe must be part of the database. Draw this database structure out in the manner we used in IS-141 (aka CPSC-135). Also, how large do you think that the database is likely to be? Could one even make a guess on this? Do this on the white board so that you are prepared to show it to the class (see step #5 below).

Using the Database to Drive an Information System

As we discussed in class, information systems employ people, machines, and/or methods to collect, manage, and use data that represent information. What is the information relevant to your chosen website? To help with this, answer the following questions:

• What information does the user gain from visiting this site?
• What information does the company gain from the user who visits this site?
• Where do you think that this information comes from? Who enters it? Could it be derived from databases that already existed in the company for other reasons?
• Who do you think maintains this information?
• How much information is there, do you think, i.e., how large do you think the underlying database is?
• Do you think that there is an alternate way (i.e., other than visiting this web site) to access this information?

Checking In

To conclude, each team will report back to the full class on what it found. When you are finished, be sure to log off of your machine.

Note: You will receive points for your participation in these labs that will count toward your "labs and projects" grade in the course. See the administrivia page for more information on this. In this lab, your participation in this final step comprises your lab work - you should see this reflected in the course grading system. See the grading page for more information on this.

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