relational database - Specifying a Functional Dependency for a Relation (Determining S2 follows from S1) -


So I have this question and I was wondering why S2 = {AD- & gt; Consider the relationship of relative R (A, B, C, D, E) and functional dependencies S1 = {AB → C, AE → D, D → B}. Which of the following sets the no of 2 SDS SDs? 

  S2 = {AD-> C} S2 = {AD-> C, AE - & gt; B} S2 = {ABC-> D, D-> B} // True Answer S2 = {ADE-> BC}

S1, and application to be closed: 

  {AD } + = {ABCD} // Why does this set from S1? What about e {AD} + = {ABCD}, {AE} + = {ABCDE} {ABC} + = {ABC}, {D} + = {B} // Right Answer {ADE} + = {ABCDE}

You do not need to include all the attributes of the closing result until you have finished S2 has all the properties on the right hand, then it happens after S 2 S1.

After closing you in this case, C is closed, which means that from S2 S1


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