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CSE 132a HW 2

# CSE 132a HW 2 - a D id P a DC Original FD’s P a> P id P...

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CSE 132a HW 2 Kenneth Law A08720808 1. a. A B C 2 b 1 c 1 2 b 1 c a 8 c 2 a 2 8 c 2 2 8 c b. A B C 2 b 1 c a 8 c 2 2 8 c c. Π AC A = 2 (R)) σ A = 2 B = 8 (R) 2. a. P a P id D id DCQ P a -> P id P a D id DCQ P a + = P a P id D id P id D -> Q P a D id DC P id D + = P id DQC P a -> D id P a DC P a + = P a P id Did P a + = P a P id D id intersect P a DC = P a D + = D intersect P a DC = D C + = C intersect P a DC = C b. This decomposition is not dependency preserving because the FD DQ -> C is not preserved. Run dependency preserving algorithm: F = P a -> P id , P id D -> Q, P a -> D id , P a D -> C, so P a P id , P id DQ, P
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Unformatted text preview: a D id , P a DC Original FD’s: P a-> P id , P id-> D id , P id D -> Q, DQ -> C c. F = P a-> P id , P id -> D id , P id D -> Q, DQ -> C d. P a P id and P id D id are automatically OK. Need to check P id D -> Q and DQ -> C. Because they are in the original FD’s, that means that they are OK as well. This decomposition is in BCNF....
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