Question

For the above given database STUDENT-PROJECT, answer the following:

a) Name primary key of each table.
b) Find foreign key(s) in table PROJECT-ASSIGNED.
c) Is there any alternate key in table STUDENT? Give justification for your answer.
d) Can a user assign duplicate value to the field RollNo of STUDENT table? Justify.

Answer 1

a) STUDENT - Roll No

PROJECT - ProjectNo

PROJECT ASSIGNED - Registration_ID

All above stated are primary keys because they are unique and cannot not be NULL.

b) Registration_ID and ProjectNo both are foreign keys because they refer to the STUDENT and PROJECT table respectively.

c) Yes, Registration_ID is an alternate key because not two students can have the same registration number.

d) No, because Roll No is a primary key in the student table and duplicate values for primary keys is not allowed.