1 votes 1 votes R(ABCD) F={ A→B, B→C, C→D, D→A } Now Decompose this into D={ AB, BC, CD } Dependency is preserved or Not ? Source : http://www.gatecrack.in/following-decomposition-dependency-preserving-not/ Databases dependency-preserving + – Anup patel asked Jan 25, 2017 Anup patel 662 views answer comment Share Follow See 1 comment See all 1 1 comment reply Ayan Kumar Pahari commented Feb 1, 2020 reply Follow Share Yes Dependency preserved. D-->A we can derive by combining AB,BC and CD via transitive dependency. 0 votes 0 votes Please log in or register to add a comment.
2 votes 2 votes No,dependency is not preserved because FD D->A is not preserved if relation is decomposed as given. Arnabi answered Jan 25, 2017 Arnabi comment Share Follow See all 4 Comments See all 4 4 Comments reply Anup patel commented Jan 28, 2017 reply Follow Share Thanks 0 votes 0 votes Dulqar commented Feb 1, 2017 reply Follow Share Can u pls explain in details how to check for it ? 0 votes 0 votes Arpit Dhuriya commented Dec 13, 2017 reply Follow Share D -> A preserve. via indirect FD 0 votes 0 votes gauravkc commented Dec 14, 2017 reply Follow Share Dependency is preserved. Check this link https://gateoverflow.in/741/gate2001-2-23 0 votes 0 votes Please log in or register to add a comment.