Question

What is Multiplicity Rule #3?

1) Whenever there is a one-to-many relationship (regardless of the minimum constraints), place the primary key of the 'one' entity into the 'many' entity as a foreign key
2) Whenever there are mandatory-minimums on both sides of a one-to-one relationship, or an optional-minimum on one side of a one-to-one relationship, the two entities should be combined into a single entity
3) Whenever there is a many-to-many relationship, (regardless of the minimum constraints), create an association table linking the two entities
4) Whenever there are optional-minimums on both sides of a one-to-one relationship, create an association table linking the two entities

Answer 1

The student seems to have confused rules related to database design with the Basic Rules of Probability. Correctly, Multiplicity in probability refers to how many times an event can occur. The multiplication and addition rules are fundamental in calculating probabilities of combined events.

Step-by-step explanation:

The question asked is related to the topic of the Basic Rules of Probability, which involves the multiplication and addition rules to determine the probability of combined events. However, the options given are actually not related to probability at all, and instead refer to rules regarding entity relationships in database design. Therefore, there is a misunderstanding in the question as presented. Nonetheless, the core concept of multiplicity in probability is the number of ways an event can occur, which is a fundamental aspect of calculating probabilities.

When considering the rules of probability, two important ones are:

• The multiplication rule—which is used to find the probability that two events, A and B, will both happen together, given by the formula P(A AND B) = P(A|B)P(B), where P(A|B) is the probability of A occurring given that B has occurred.
• The addition rule—used to find the probability that at least one of two events, A or B, will happen, given by the formula P(A OR B) = P(A) + P(B) − P(A AND B). This rule accounts for the fact that the intersection of A and B (the probability that both events occur) has been counted twice and therefore must be subtracted once.

It is important to note that these rules apply to the field of probability and have different implications compared to entity-relationship rules in database design.