Question

5. The Hudson Engineering Group (HEG) has contacted you to create a concep- tual model whose application will meet the expected database requirements for the company's training program. The HEG administrator gives you the following description of the training groups operating environment. (Hint: Some of the fol- lowing sentences identify the volume of data rather than cardinalities. Can you tell which ones?) The HEG has 12 instructors and can handle up to 30 trainees per class. HEG offers 5 Advanced Technology courses, each of which may generate several classes. If a class has fewer than 10 trainees, it will be canceled. Therefore, it is possible for a course not to generate any classes. Each class is taught by one instructor. Each instructor may teach up to 2 classes or may be assigned to do research only. Each trainee may take up to 2 classes per year Given that information, do the following: Define all of the entities and relationships. (Use Table 4.4 as your guide.) Describe the relationship between instructor and class in terms of connectivity. cardinality, and existence dependence.

Answer 1

a)

From the above table, many of the relationships are optional and mandatory A COURSE does not necessarily generate a class during each training period.(some courses may be taught every other period or during some other specified time frames. Therefore, it is reasonable to assume that CLASS is optional to COURSE Each Class must be related to a COURSE.(The lass must cover designated course material!) Therefore, COURSE is mandatory to CLASS. Some instructors may teach a class every other period or even rarely. Therefore, it is reasonable to assume that CLASS is optional to INSTRUCTOR during any enrolment period. This option makes sense from an implementation point of views, too. For example, if you appoint a new instructor, that instructor will not-yet-has taught a class. Not all trainers are likely to be enrolled in classes during some time period. In fact, in a real world setting, many trainees are likely to get informal-on the jobll training without going to formal classes

b)