Functional Dependencies PPT Notes

Replies

• 

  ISHAN TOPRE

  Re: Functional Dependencies
  
  Also see this! 😛
• 

  kevin88

  Hello
  
  I am having a problem understanding dependency theory using Armstrong's Axioms, I have researched this online and I understand the axioms however I am struggling to understand a particular example. Can anyone provide me with any advice or help?
  
  Can I post the example here?
  
  Thank you
• 

  ISHAN TOPRE

  Yes of course you can post your query here. Our CS/IT people will try to explain you the theory so that you will be able to solve your problem. 😀
• 

  kevin88

  Thank you ishutopre
  
  I have two examples with answers but I do not understand how the answer has been derived:
  
  Example 1:
  Given
  R < A= {V,W,X,Y,Z},
  Gamma = { 1. V -> Y, 2. YW -> Z
  3. Y -> W}>
  
  RTP(required to prove) VWY -> Z and VXY ->Z
  
  Answers:
  VWY -> WY -> Z
  VXY -> Y -> YW -> Z
  augment 3 by Y Y -> W
  
  Example 2:
  Given the following relation
  R < A = {M,N,O,P,Q,R,S},
  Gamma = {Q->MO, S->R, M->SP}>
  
  prove that PM->R
  
  Answer:
  PM -> SP -> S -> R
  M -> SP augment by P