Why Is Sno, Pno=>Qty, Sname=>Qty in 3NF?

  • Comp Sci
  • Thread starter shivajikobardan
  • Start date
In summary, the conversation discusses the concept of third normal form (3NF) and how it applies to the given functional dependencies (FDs). The participants agree that for the first two FDs (Sno,Pno=>Qty and Sname,Pno=>Qty), the LHS is a super key and the RHS is a non-prime attribute, making them in 3NF. However, there is a disagreement about the last two FDs (Sno=>Sname and Sname=>Sno). While one participant argues that they are not in 3NF because they do not follow the rule of LHS being a super key, the other participant points out that they serve as lookup tables to translate between sno and sname.
  • #1
shivajikobardan
674
54
Homework Statement
3NF third normal form
Relevant Equations
none
Sno,Pno=>Qty
Sname,Pno=>Qty
Sno=>Sname
Sname=>Sno

To be in 3NF, LHS should be super key and RHS should be non-prime attribute.
It holds true for first 2 FDs. But for the last two, it doesn't hold true. So, why is it in 3NF?
chatGPT says it holds true for all FDs, but I can't see how.
 
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  • #2
The last two look like lookup tables to translate between sno and sname. Given sno I can find sname and given sname I can find sno.
 
  • #3
shivajikobardan said:
Homework Statement:: 3NF third normal form
Relevant Equations:: none

Sno,Pno=>Qty
Sname,Pno=>Qty
Sno=>Sname
Sname=>Sno
This is impossible to answer without knowledge of what data are contained in the columns, however assuming Sname represents a person's name, and given the fact that two people can have the same name what do you think about your statement that Sname,Pno=>Qty is in 3NF?
 

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