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Can you help me to normalize a table. The exercise say: "Find the functional dependencies (FD) and normalize the table" (i guess this means to put it in 3NF):

A |B |C |D
------------
a1|b1|c1|d1

a2|b1|c1|d1

a1|b1|c2|d1 

a5|b2|c5|d1 

a6|b1|c7|d2 

a3|b1|c1|d4

a1|b5|c4|d3

I didn't find any FD. The simple types of FD are:

{A} -> {B}

{A} -> {C}

...

{B} -> {A}

...

{D} -> {A}

{D} -> {B}

{D} -> {C}

Altogether 12. I refer from http://en.wikipedia.org/wiki/Database_normalization and looked at this kb article from MSDN: http://support.microsoft.com/kb/283878

Brian Tompsett - 汤莱恩
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venko_js
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1 Answers1

1

I believe that the only FD that might exist there is C -> B. That is, all the other ones do not hold...

However, FD-s are normally inferred from domain knowledge, not from some data :)

In case you want to study more about these, I would recommend an on-line (free) DB course, held by a professor at Stanford University: https://www.coursera.org/course/db.

No offence, but this looks like homework :)

turdus-merula
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