Case Study: BCS, Part 3

The new enrollment system takes requests from three areas: student kiosks, registrar workstations, and the World Wide Web. In all cases, requests go through a basic validation processor. If all the required information is present, the request is sent on to the business tier.

A business rules component does a more thorough completeness check. It then checks the student's financial status. If he does not exceed established thresholds, the financial component approves the request. The enrollment is then matched against course availability and whether the student meets course prerequisites. If both conditions are met, the student is enrolled, and a positive response is returned to him or her. The enrollment is also sent through a database "persistence" layer to the main SQL Server tables.

Anything that will cause denial of the enrollment triggers a negative response to the student along with an explanation. Students have an electronic appeal process that triggers an e-mail to the professor or a registrar. At this point, there are no response time commitments. It could take a day or two to get it resolved.

The registrars go through basically the same process as the students.

Finally, in physical design, you concern yourself with performance, maintainability, extensibility, scalability, availability, security, and properties/methods/events. Therefore, follow these guidelines:

• Look for operations (methods) that the target system might need to perform. Create a list of these operations from the list of the verbs.

• Look for properties (nouns and adjectives), such as "class size," "name," and "cost."

• Identify geographical constraints and unusually large distances between tiers.

• Look for workflow through the system. Workflow is particularly important for the Microsoft exam.

A useful strategy for the exam is drawing a workflow diagram that shows the flow of data through the system. Using numbers to indicate sequence can also be helpful for certain question styles. Figure 12.4 shows a sample of what a workflow diagram for BSC might look like.

Figure 12.4. A workflow diagram for the BSC enrollment system.

Standards and Processes

Not much information in the case study would help you in the area of standards and processes, but one item does stand out. Whenever some, or all, of the team is "new," you should look for an opportunity to take advantage of Enterprise Templates. In the BSC case study, you might expect to see a professor, one who teaches the C# classes, creating templates that the graduate assistants use to build the solution. Also, because you know that virtually every team is more than one person, SourceSafe standards, coding standards, and best practices are always called for.

As one last issue, whenever you see specific hourly wages in a case study, you might be expected to calculate the return on investment (ROI). The ROI for BSC is a straightforward calculation.

It is forecast that 8,000 students will use the new system. That means you avoid the following costs of having those students stand in line and be serviced by a registrar:

(8,000 ÷ 8) x $20/hour = $20,000

Multiply that by six semesters (because the case study says that BSC hopes the system will pay for itself in three years):

$20,000 x 6 = $120,000

So if you can get this solution built for $120,000, you achieve your goal and have an ROI equal to 1.

There is an implied assumption that the graduate assistants maintaining the solution are not getting paid (sorry, GAs), but are doing it to add to their resume (or to get on good terms with the professor, I suppose).

You've covered strategies for reading and drawing out information for the seven major objectives of the Microsoft exam. Of course, when you're taking notes, logic and common sense should prevail. Don't attempt to draw architectural masterpieces. If you sense you are slipping behind the allotted time, you might want to wait to draw more complicated diagrams until you are sure they are required. Then, while rereading the case study, you could sketch the ones discussed in this chapter.

Now it's time to quickly review the PASS MADE attributes, which have been covered in more depth in previous chapters.