[satislikev]

Hello.
I'm studying database and there is something that is unclear for me if we have R1(A,B,C), R2(B,D) and we have functional dependencies as A→B, A→C, B→A, and A→D and those that can be derived from these functions. Is it possible for this schema to be BCNF?
I mean this schema is decomposition of a major relation. but how we can found the first relation and how is possible to find out if this one is decomposed by BCNF?
Also i see the link between R1 and R2 is A→D, and i can derive A→BC and AB is key, can someone help me understand this better?
Thank you.