Multiple choice

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?

  1. 8, 8

  2. 120, 8

  3. 960, 8

  4. 960, 120
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A Correct answer
Explanation

The boundary cases are when either all the tuples of Enroll table belong to one roll number, so there can be at most 8 roll number and course number combinations or the other case is when all the tuples belong to different roll no. this also has 8 tuples. So (8,8) = (max,min)

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