
Database Systems 6th Edition by Ramez Elmasri, Shamkant B. Navathe
النسخة 6الرقم المعياري الدولي: 0136086209
Database Systems 6th Edition by Ramez Elmasri, Shamkant B. Navathe
النسخة 6الرقم المعياري الدولي: 0136086209 تمرين 3
Algorithm 15.5. Relational Decomposition into BCNF with Nonadditive Join Property
Input: A universal relation R and a set of functional dependencies F on the attributes of R.
1. Set D := {R} ;
2. While there is a relation schema Q in D that is not in BCNF do
{
choose a relation schema Q in D that is not in BCNF;
find a functional dependency X → Y in Q that violates BCNF;
replace Q in D by two relation schemas (Q - Y) and (X ∪ Y);
} ;
-Show that the relation schemas produced by Algorithm 15.5 are in BCNF.
Input: A universal relation R and a set of functional dependencies F on the attributes of R.
1. Set D := {R} ;
2. While there is a relation schema Q in D that is not in BCNF do
{
choose a relation schema Q in D that is not in BCNF;
find a functional dependency X → Y in Q that violates BCNF;
replace Q in D by two relation schemas (Q - Y) and (X ∪ Y);
} ;
-Show that the relation schemas produced by Algorithm 15.5 are in BCNF.
التوضيح
This is trivial, since the alg...
Database Systems 6th Edition by Ramez Elmasri, Shamkant B. Navathe
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