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 excerpt does not provide any information about the cardinality of the relationship between ENTITY A and ENTITY B, so we cannot assume that it is a one-to-one relationship. However, it does state that "many instances of ENTITY A may be related to one instance of ENTITY B," which means that B can have many related instances of A. The excerpt does not provide any information about the degree of ENTITY B or whether it is a weak entity.

Given Only the Following Excerpt of an E-R Model