ch07 - 7. 2 (relational scheme) (relational scheme) ? i. ,...

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Unformatted text preview: 7. 2 (relational scheme) (relational scheme) ? i. , , . : iii. (anomaly) 3 : , 100 C413 A 4 100 E412 A 4 200 C123 B 3 300 C312 A 1 300 C324 C 1 300 C413 A 1 400 C312 A 4 400 C324 A 4 400 C413 B 4 400 E412 C 4 500 C312 B 2 (anomaly) example : example : 4 (2) (deletion anomaly) (deletion anomaly) 200 'C123' 3 (triggered deletion) (loss of information) (insertion anomaly) (insertion anomaly) 600 2 ( ) (update anomaly) (update anomaly) 400 4 3 400 4 (inconsistency) 5 (decomposition) (normalization) 6 : : ( ) (schema transformation) 7 (FD) R , X Y Y X X Y X Y ( ) X (determinant) Y (dependent) X, Y 8 (2) Note Note R...
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ch07 - 7. 2 (relational scheme) (relational scheme) ? i. ,...

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