Typically, a Person subjects h’self to Employment in order to do a particular job—to hold a Position—a defined role in a company. Figure 13-2 shows Position Assignment as the fact that a particular Person employed by an Organization (that is, subject to an Employment) is (for a period of time at least) assigned to exactly one Position.
Figure 13-2: Position Assignments
Specifically, each Position Assignment must be based on one and only one Employment and must be to one and only one Position. Each Position, then, must be an example of one and only one Position Type.
Note that the Position Type itself must be the responsibility ...