1 votes 1 votes Given a relation R{A, B, C, D, E, H} and having the following functional dependencies : {A → BC, CD → E, E → C, D → AEH, ABH → BD, DH → BC} The number of candidate keys for relation R is ________. Databases databases database-normalization + – Tuhin Dutta asked Dec 15, 2017 Tuhin Dutta 2.6k views answer comment Share Follow See all 5 Comments See all 5 5 Comments reply Show 2 previous comments Tuhin Dutta commented Dec 15, 2017 reply Follow Share Yes, but why we should be consider AH (two attributes) as candidate key, when only a single attribute 'D' is a candidate key. Shouldn't we only try to find any other single attribute candidate key? I know I'm wrong but I want know the reason. Thanks 0 votes 0 votes joshi_nitish commented Dec 15, 2017 reply Follow Share @Tuhin, candidate key is always minimal, it means that proper subset of candidate key can not be candidate key. now it does not matter that candidate key is made up of 1 attribute or 100 attributes but it should be minimal, 2 votes 2 votes Ashwin Kulkarni commented Dec 15, 2017 reply Follow Share Yes you can try other single attribute candidate keys, But their closure won't give all attributes. 0 votes 0 votes Please log in or register to add a comment.