0 votes 0 votes Databases made-easy-test-series databases relational-algebra + – pkb asked Feb 7, 2017 • edited Mar 5, 2019 by adeebafatima1 pkb 436 views answer comment Share Follow See all 0 reply Please log in or register to add a comment.
0 votes 0 votes Max record possible in R1/R2 is |R1| when R2 is empty. Digvijay Pandey answered Feb 7, 2017 Digvijay Pandey comment Share Follow See all 4 Comments See all 4 4 Comments reply Akriti sood commented Mar 8, 2017 reply Follow Share in A/B,we get those tuples in A which are true for every row of B. since B is empty here,so how is answer |A|?? 0 votes 0 votes Pavan Kumar Munnam commented Mar 8, 2017 reply Follow Share since it is empty there is no condition so no filtering of data!! 0 votes 0 votes 2018 commented Mar 8, 2017 reply Follow Share in division query give output for that tuples which matches every qualifying record from another table in the whole process of devision this "for all" is the keyword because of this only in empty case it true result. "for all" gives true in case of empty x https://en.wikipedia.org/wiki/Vacuous_truth 0 votes 0 votes Akriti sood commented Mar 8, 2017 reply Follow Share thanks..i got it:) 0 votes 0 votes Please log in or register to add a comment.
