Question-47

Let \(R(A,B,C,D)\) be a relational schema with the following functional dependencies :
\(A \rightarrow B\), \(B\rightarrow C\), \(C \rightarrow D\) and \(D \rightarrow B\).

The decomposition of \(R\) into \((A,B), (B,C), (B,D)\)

• gives a lossless join, and is dependency preserving
  
• gives a lossless join, but is not dependency preserving
  
• does not give a lossless join, but is dependency preserving
  
• does not give a lossless join and is not dependency preserving

Answer

• gives a lossless join, and is dependency preserving
  
• gives a lossless join, but is not dependency preserving
  
• does not give a lossless join, but is dependency preserving
  
• does not give a lossless join and is not dependency preserving