Relational-Algebra
|
Question 17
|
Consider the following relation schema pertaining to a students database:
Student (rollno, name, address) Enroll (rollno, courseno, coursename)
Where the primary keys are shown underlined. The number of tuples in the Student and Enroll tables are 120 and 8 respectively. What are the maximum and minimum number of tuples that can be present in (Student * Enroll), where ‘*’ denotes natural join ?
|
8, 8
|
|
|
120, 8
|
|
|
960, 8
|
|
|
960, 120
|
Question 17 Explanation:
Natural join is a JOIN operation that creates an implicit join cause for you based on common columns in the two tables being joined.
→ In the question only enroll Id’s are same with the student table.
→ The no. of minimum and maximum tuples is same i.e., 8, 8.
→ In the question only enroll Id’s are same with the student table.
→ The no. of minimum and maximum tuples is same i.e., 8, 8.
Correct Answer: A
Question 17 Explanation:
Natural join is a JOIN operation that creates an implicit join cause for you based on common columns in the two tables being joined.
→ In the question only enroll Id’s are same with the student table.
→ The no. of minimum and maximum tuples is same i.e., 8, 8.
→ In the question only enroll Id’s are same with the student table.
→ The no. of minimum and maximum tuples is same i.e., 8, 8.