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I have a general understanding of Heath Theorem but I'm having trouble getting my head around this question:

Use the functional dependencies to carry out a non-loss decomposition in line with Heath’s Theorem,
to produce a set of tables in 3NF (3 rd Normal Form).

Say why each decomposed table is in 3NF and no longer just 2NF

Say I have the following FD:

{orderId} -> {employeeId, unitPrice}

Does this mean I get the table being decomposed (parent) use SQL to convert it to multiple tables (decomposed). From the above the result would include a table with the fields:

orderId, employeeId and unitPrice

To explain 3NF vs 2NF do I just confirm there are no longer any transitive dependencies in the new table. This is my understanding of the 3NF requirement.

How do I go about explaining all of the above with relation to Heath's Theorem ?

markus
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jim
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    You might have more luck here http://cstheory.stackexchange.com/ – Adam Rackis Nov 16 '11 at 18:24
  • Well, I posted the same question there and it has been closed. That site is only for research level computer science. – jim Nov 17 '11 at 09:02
  • Never heard of Heath's theorem... I guess I've been doing SQl for too long. If I understand correctly what it says, I'd guess you'd start with a table (orderId, employeeId, unitPrice), with a FD orderId->employeeId, and realize that your table can be stored as two tables (orderId,employeeId) and (orderId, unitPrice)... – pascal Apr 17 '12 at 16:08

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