Given only the following excerpt of an E-R model:
Which of the following is known to be true?
A) A single instance of ENTITY A must be related to one instance of ENTITY B.
B) Many instances of ENTITY A may be related to one instance of ENTITY B.
C) ENTITY B has a degree of many.
D) ENTITY B is a weak entity.
E) Both A and C are true.

Question

Given only the following excerpt of an E-R model: 
Which of the following is known to be true?
A) A single instance of ENTITY A must be related to one instance of ENTITY B. 
B) Many instances of ENTITY A may be related to one instance of ENTITY B. 
C) ENTITY B has a degree of many. 
D) ENTITY B is a weak entity. 
E) Both A and C are true.

Quizplus · Accepted Answer

The code "TB4532" is not related to the question and can be ignored. The excerpt shows that there is a relationship between ENTITY A and ENTITY B, but it does not specify the cardinality of the relationship. Therefore, we can only conclude that many instances of ENTITY A may be related to one instance of ENTITY B, but not that a single instance of ENTITY A must be related to one instance of ENTITY B. ENTITY B's degree and whether it is a weak entity cannot be determined from the given information.

Given Only the Following Excerpt of an E-R Model