0 votes 0 votes closed as a duplicate of: GATE CSE 2009 | Question: 45 Databases tuple-relational-calculus + – ankitgupta.1729 asked Dec 16, 2017 closed Dec 16, 2017 by srestha ankitgupta.1729 380 views comment Share Follow See 1 comment See all 1 1 comment reply Ashwin Kulkarni commented Dec 16, 2017 reply Follow Share I’m thinking 3 & 4 would be the same. 0 votes 0 votes Please log in or register to add a comment.