Database Reference
In-Depth Information
Open-ended
1. What are the most frequent problems you have in buying
topics from a book store?
2. Of the problems listed above, what is the single most
troublesome?
Closed
1. The tool is used as part of the program development cycle to
improve quality. How important is the tool?
1 2 3 4 5 (circle appropriate response, where 5 is the highest score)
A good questionnaire will probably be a combination of both types of
questions. It's also important to (a) make sure that you format your ques-
tionnaire for easy readability (lots of white space and even spacing), (b)
put all the important questions first (in case they don't finish the survey),
and (c) vary the type of question so that they don't just circle 5s or 1s all
the way down the page.
Diagramming or Modeling the System
There are a wide variety of techniques you can use to diagrammatically
describe your problem and its solution, and there are a wide variety of
tools that can assist you in drawing these diagrams. One of the diagram-
matic techniques is flowcharting, and the tool of choice is Microsoft Visio.
One of the most practical tools is the data flow diagram (DFD), as shown
in Figure 7.3. DFDs are quite logical, clear, and helpful when building sys-
tems—even web-based systems. All inputs, outputs, and processes are
recorded in a hierarchical fashion. The first DFD, referred to as DFD 0,
is often the system from a high-level perspective. Child DFDs get much
more detailed. Figure 7.3 is a snippet of a real online test system. It's a
rather complicated system that lets people take tests online. This particu-
lar DFD shows the data flow through the log-in process. The rectangular
boxes (e.g., D5) are the data stores. Notice that D5 is an online cookie. D1,
on the other hand, is a real database. It's a relational database, and this is
one particular table. The databases and their tables are defined in a data
dictionary. The square box is the entity (i.e., test taker) and can be a per-
son, place, or thing. The other boxes are process boxes. Process 1.1 is the
process for Get Name, and there will be an associated child DFD labeled
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