List all the entities that interact with the TIMS system. Start by reviewing the data library, previous e-mail messages, DFDs, and other documentation.

Question

What will be an ideal response?

Answer 1

Based on the overall fact situation, students might submit a list of entities that includes the following:
STUDENT
INSTRUCTOR
TRAINING ADMINISTRATOR
CORPORATE CLIENT
COURSES
In addition, the ACCOUNTING SYSTEM can be shown as an external entity that interacts with the TIMS system. If students use object modeling in addition to DFDs, they will find that DFD entities tend to be represented as actors in an object model (see Chapter 6 for more information about object modeling). Also, an object model probably includes object classes that appeared as data stores in the process-oriented DFDs.
Regardless of the modeling method, it is important for students to realize that an entity can represent an event or transaction, such as an airline reservation. For example, when a student takes a course at SCR, the event that is recorded might be called a REGISTRATION RECORD, or a TRAINING RECORD. Students should understand that these objects are associative entities, which are explained in the chapter. You might call attention to Figure 9-18 on page 363, to point out the associative entity called ORDER-LINE. Again, remind students that an entity can be a person, place, thing, or event — and an order line is an example that involves two other entities (ORDER and PRODUCT).
Also remind students that in data design, associative entities are not always apparent at first and sometimes are identified after the logical analysis process. Also point out that associative entities typically are needed whenever an M:N relationship exists. In these situations, there usually is no common field, and the associative entity joins two other entities.