5. The Hudson Engineering Group (HEG) has contacted you to create a conceptual model whose application will meet the expected database requirements for the companys training program. The HEG administrator gives you the description (see below) of the training groups operating environment. (Hint: Some of the following 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 five Advanced Technology courses, each of which may generate several classes. If a class has fewer than ten 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 two classes or may be assigned to do research only. Each trainee may take up to two classes per year.

Given that information, do the following:

Define all of the entities and relationships. (Use Table 4.4 as your guide.)

The HEG entities and relationships are shown in Table P4.5a.

Table P4.5a The Components of the HEG ERD

ENTITY	RELATIONSHIP	CONNECTIVITY	ENTITY

As you examine the summary in Table P4.5a, it is reasonable to assume that many of the relationships are optional and that some are mandatory. (Remember a point we made earlier: when in doubt, assume an optional relationship.)

Note that a real world database design requires the explicit recognition of each relationships characteristics. When in doubt, ask the end users!

Describe the relationship between instructor and class in terms of connectivity, cardinality, and existence-dependence.

Both questions (a) and (b) have been addressed in the ER diagram shown in Figure P4.4b.