3 votes 3 votes Answer is 2 minimal and 2 canonical covers. Please give full explanation of how to solve. Databases database-normalization databases canonical-normal-form + – Shefali asked Jul 22, 2015 Shefali 2.0k views answer comment Share Follow See all 0 reply Please log in or register to add a comment.
6 votes 6 votes Miinimal (canonical) cover of a set of FDs is the minimal set of FDs such that all other FDs can be derived. So, {X -> Y, Y -> Z, Z-> X}, {X->Z, Z-> Y, Y->X} Arjun answered Apr 8, 2016 Arjun comment Share Follow See all 0 reply Please log in or register to add a comment.
1 votes 1 votes minimal cover is known as canonical cover here two canonical cover are possible we get canonical cover by eliminating redundant FDs 1st cv : becoz z->x so we can replace x by z in y->xz ( becoz if child derivates sumthing dan child will surely do dat) nd get y->z (1) by spliting we cn write x->yz as x->y (2) nd x->z(3) if we combine (2) nd (1) by union rule we get x->z which is nothing bt (3) FD so we cn elliminate (1) nd (2) becoz de r redundant nd we got 1st canonical cover as {x->z} similarly we got 2nd minimal cover as {y->z}. see this:https://gateoverflow.in//blog/13/shortest-way-to-find-minimal-cover Rohan Ghosh answered Jul 22, 2015 Rohan Ghosh comment Share Follow See all 2 Comments See all 2 2 Comments reply Shefali commented Jul 25, 2015 reply Follow Share But with these two covers x -> z and y -> z, we lost the relation between x and y. Neither do we have x->y nor y->x 0 votes 0 votes AshwiniT commented Jan 27, 2018 reply Follow Share If those two are minimal dependency, thnt there that is lossy .. Llss in FDs 0 votes 0 votes Please log in or register to add a comment.
1 votes 1 votes x→y and z→x are minimal cover ManojK answered Apr 7, 2016 • edited Apr 7, 2016 by ManojK ManojK comment Share Follow See all 2 Comments See all 2 2 Comments reply Arjun commented Apr 8, 2016 reply Follow Share x -> z? 0 votes 0 votes ManojK commented Apr 8, 2016 reply Follow Share Sir if remove x -> z then by taking (x)+=xyz So is it n,t redudant . 0 votes 0 votes Please log in or register to add a comment.