I have this problem decomposing a relation schema into a set of开发者_高级运维 schemas that are in 3NF.
I have this relation schema: R= (A, B, C, D, E, F)
With the following set F of functional dependencies:A → ABCDEF
B → C D → ECan anyone help me out?
RA = (A, B, D, F)
RB = (B, C)
RD = (D, E)
Why? 3NF requires the removal all transitive dependencies.
In R, C is transitively dependent on A through B, and the same is true for E through D. To remove those properties, you need to decompose the tables such that those transitive relationships are removed, which you do by extracting the table and using the middle term as keys.
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