i'm solving a multi part question regarding candidate keys and functional dependencies.

now i've already found 2 dependencies(the canonical covering of the functional dependencies contains only 3 dependencies) in the previous parts of the question: $D\to BE, CE \to AD$ ($R=A,B,C,D,E$, R is in BCNF). how can i find the third and last one? i need to find in order to figure the candidate keys

(didn't post the previous part of the questin because they're irrelavant, just posted what i found and all the needed information from the question).

thank you very much for your help!

  • $\begingroup$ Which are the initial given dependencies? D->BE and CE->AD? Then there are four dependencies in the canonical cover, not three (and the relation is not in BCNF). $\endgroup$ – Renzo Jan 16 '18 at 13:29
  • $\begingroup$ thank you for replying @Renzo. i was given D->BE, found CE->AD and there should be one more dependency i should find and i am not sure how. it is said that the canonical covering consists of only 3 dependencies and R is in BCNF $\endgroup$ – BeginningMath Jan 16 '18 at 14:03
  • $\begingroup$ don't know how to find the remaining dependency $\endgroup$ – BeginningMath Jan 16 '18 at 14:14
  • $\begingroup$ I need all the original depedencies, there is only D->BE? So how did you find CD->AD? $\endgroup$ – Renzo Jan 16 '18 at 14:43
  • $\begingroup$ obtained it from a previous sub question about database modeling(entity design). how is it possible to know what is the third one after D->BE and CD->AD? $\endgroup$ – BeginningMath Jan 16 '18 at 14:49

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