dependency preserving

Let $$R\left( {A,B,C,D} \right)$$ be a relational schema with the following functional dependencies: $$A \to B,\,\,B \to C,\,\,C \to D$$ and $$D \to B.$$ The decomposition of $$R$$...

Consider a schema $$R(A,B,C,D)$$ and functional dependencies $$A \to B\,\,$$ and $$C \to D\,\,$$. Then the decomposition of $$R$$ into $${R_1}\left( {AB} \right)$$ and $${R_2}\left...