2 votes 2 votes Let R and S be two relations, and l be an attribute common to R and S. Let c be a condition over the attributes common to R and S. Prove or disprove the following: Databases relational-algebra + – vix28 asked Apr 26, 2016 vix28 478 views answer comment Share Follow See all 0 reply Please log in or register to add a comment.
2 votes 2 votes i) invalid ii) valid srestha answered Apr 26, 2016 srestha comment Share Follow See 1 comment See all 1 1 comment reply Rishabh Gupta 2 commented Dec 4, 2017 reply Follow Share Any explanation? I understand i is invalid. But how to prove that ii is valid? 0 votes 0 votes Please log in or register to add a comment.