CSC343 Test 3 Question Fall 2020
[7 marks]
Consider relation R(A, B, C, D, E) with the following minimal basis S={AB¡úE, C¡úBD, BD¡úA}
1. Suppose R is decomposed into two relations: R1 = ACE and R2 = ABD. Give an instance of R that can be used to demonstrate that this decomposition is lossy. Then project that instance onto R1 and R2 and rejoin it. Finally, explain what in the result indicates that the decomposition of R into R1 and R2 is lossy.
2. Define a different decomposition of R into two relations that is lossless. Then use the Chase Test to prove that it is lossless.
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