2 2 votes Every binary relation is in a)bcnf b)3nf c)4nf d)pjnf Databases database-normalization databases bcnf + – iamHarin 2.6k views answer comment Share Follow Print See all 2 Comments 2 2 Comments reply Shubhanshu commented Jul 28, 2017 reply Follow flag It depends on the functional dependencies it has. 0 0 replyShare Deepak Poonia commented Jul 17, 2024 reply Follow flag Every binary relation is in BCNF.Video Explanation with Proof: https://youtu.be/SffSx6Kyv_s?feature=shared 0 0 replyShare Please log in or register to add a comment.
3 3 votes Every Binary Relation (A relation with two attributes) is always in BCNF! For Example, there is a relation R = {A,B}. So, there are three possible functional dependencies here. A->B {C.K =A} or B->A {C.K = B} or AB->AB {CK = AB} No viaolation of BCNF in any of the above three cases, hence R is in BCNF! Manu Thakur answered Jul 28, 2017 • edited Jul 28, 2017 Manu Thakur comment Share Follow See all 7 Comments 7 7 Comments reply Arjun commented Jul 28, 2017 reply Follow flag So it is in 1NF also? 0 0 replyShare Manu Thakur commented Jul 28, 2017 i edited Jul 28, 2017 reply Follow flag Yes, and it has to be in 1NF, because RDBMS relations don't allow multiple values. only ER diagrams allow multivalue attributes. 0 0 replyShare Arjun commented Jul 28, 2017 reply Follow flag But 1NF is also defined for a "relation" https://en.wikipedia.org/wiki/First_normal_form 0 0 replyShare Manu Thakur commented Jul 28, 2017 i edited Jul 28, 2017 reply Follow flag yes, it is defined. but mutlivalue attributes are not defined for relations. for example R={A,B,C,D} there is no way to represent multivalue attributes here. while in ER diagram we have a representation for it. So, every relation will be in 1NF by default. and what they have shown there, it's for our understanding only, I think. 0 0 replyShare Arjun commented Jul 28, 2017 reply Follow flag Not really. 1NF says that the range of a FD must be a value and not a set of values. In a simple relation, range can be a value, set of values or even set of set of values. 0 0 replyShare Manu Thakur commented Jul 28, 2017 reply Follow flag For your reference from Korth: 0 0 replyShare skyby commented Jul 29, 2017 reply Follow flag we generally consider highest normal form, therefore if it is in BCNF then it must be in 1NF also.(I think) 0 0 replyShare Please log in or register to add a comment.
