5 votes 5 votes Given R with n tuples S with m tuples n<m then How many minimum and maximum tuples in follwing relations . Please Justify with Reason / Examples R-S S-R R Left Join S R Natural Join S R/S S/R Databases databases + – Dulqar asked Jan 6, 2017 • edited Jan 6, 2017 by Dulqar Dulqar 9.7k views answer comment Share Follow See all 11 Comments See all 11 11 Comments reply Show 8 previous comments Dulqar commented Jan 7, 2017 reply Follow Share Confused ! What is correct one ? :( 1 votes 1 votes santhoshdevulapally commented Jan 7, 2017 reply Follow Share @pc,if no tuple is common then we go for cartesian product.am i right?? 1 votes 1 votes pC commented Jan 7, 2017 reply Follow Share Exactly what I have told above. Even shared few References :) 0 votes 0 votes Please log in or register to add a comment.
4 votes 4 votes [Someone should verify . This is what I think] 1. R UNION S max : n+m Reason : union we add all the tuples from both relations. ie When R and S have no common tuple. min: n Reason : The minimum is n (the greatest of the two sizes, m and n). When all the tuples of R also exist in S. 2. R INTERSECTION S max : m ( m<n ) Reason : both relation contains same tuples then we may get maximum m keys min: 0 Reason : taking m=n=null if no common tuples in both relations 3. R - S max : m Reason : if they are disjoint then in R-S we will get all tuples of R min: 0 Reason : if all tuples in R is also present in S 4. S - R max : n Reason : as explained above min: n-m Reason : m<n there will be some tuples in S after deleting the common tuples 5. R natural join S max : n*m Reason : if no matching key constraints natural join will produce Cartesian product ) min: 0 Reason : Identical with case 2 (INTERSECTION). 6. R LEFT OUTER JOIN S max : m*n Reason : if all rows in left tables matches with all rows in right table min: m (could be 0 when m= 0) Reason : The minimum is 1 when m=1 , minimum is 2 when m=2, minimum is 0 when m=0 7. R / S max : m Reason : when n=0 min: 0 Reason : Consider that relational division is similar to integer division. 3 / 7 gives 0 in integer division for example. Try to convert this into relational division pC answered Jan 7, 2017 pC comment Share Follow See all 3 Comments See all 3 3 Comments reply smsubham commented Sep 25, 2017 reply Follow Share For 7th point, if m=0 then R / S has zero tuples. Isn't it? 0 votes 0 votes Shinigami555 commented Nov 5, 2018 reply Follow Share 6.max of left natural join How will all rows of left table match with all of right? 0 votes 0 votes Rishav Kumar Singh commented Dec 21, 2018 reply Follow Share For natural join mn is max. Case 1: if there is a common attribute between and , and every row of R matches with the each row of S - i.e., the join attribute has the same value in all the rows of both and , Case 2: If there is no common attribute between R and S . Min is 0. If There is a common attribute between R and S and nothing matches. 1 votes 1 votes Please log in or register to add a comment.