UHCL 23a Graduate Database Course - Minimal Covers Example

[orhancanceylan]

Thank you very much for that video ! But I have a question, after doing all of these steps, will the minimal cover also be a boyce codd normal form ? Or is each left side of the FDs a key ?

[sparklestar47]

thank you so much professor...!! it was so helpful for me!..

[harclevuyk]

Thnx a lot Professor . You are a great person . It was very hard for me to understand that using my professor's lessons . Blessed are those who give without remembering.

[danielrugeles]

Excellent. Thank you.

[kksandyrox]

what if there are 3 elements on the right hand side? how to decompose and move forward? ex:

D-->AEH?

[heroclix0rz]

@kksandyrox You can always break an 'implies' statement down so that the left hand side implies each of the right hand sides individually.

So D-->AEH == D-->A, D-->E, D-->H.

Side Note:

It is NOT correct to say that: AEH-->D == A-->D, E-->D, H-->D.

The only exception is: AEH-->A == AE-->A == AH-->A == A-->A

[teodorvb]

You just saved my live. This was the ultimate help.

[atulrana102]

thanks..got everything clearly..I needed it for my exams badly..

[rnramakr]

excellent and concise explanation. Thanks!

[eyerecorddrums]

Great video, helped a lot!

[Travigne]

thanks alot. Regarding to remove extraneous attributes, for example if i have F = {AE->BC, BE->C, AE->D}. Can we reduce attribute on the right hand side of BC? If yes, how do we know?

[chinamd1971]

I like the video thanks for sharing. I am having a bit of a struggle with my attribute set ABCDEFGH. Do all attributes have to be present in a minimal cover?

[nxjohny]

Just a short question: What should i do, if in the second step, when we eliminate the extraneous member of the left hand side, for example AB the left hand side, and the closure of A contain B and B closure contain A.

[GaryBoetticher]

@nxjohny You may eliminate either the A or the B. Given a set of FDs, there may be 2 more minimal covers.

[nxjohny]

@GaryBoetticher

Thank you so much!!! :)

[TheNemoooz]

great video, but I have one question though. In the 2nd step of removing extraneous left attributes, and we wanted to find the closure of C in the FD

(BC -> A), why did we use this same functional dependency that I am trying to reduce. I am trying to reduce the BC and therefor shouldn't use it, maybe just use the C ??

[juansemoralesmusic]

@TheNemoooz since we have C-> B (bottom line), then C closure will include the B, and therefore the A as well (in the FD we are analyzing)

[BlackBannerFilms]

thanks from Sweden!

[aruvimaha]

excellent and clear . Thank u professor.

[xzillione]

wow this is awesome.. u just helped me past my final!!

[AshleyJae12]

Thank you so much, your detailed explanation really saves me lots of time struggling to understand this topic just before examinations :D

[combovercool]

Wow, really helpful. Thank you!

[yuzyirmibir]

oh it helped a lot! Thanks a bunch!

[johnds123]

Thank you so much...I so wish you were my Database teacher right now...

[hiddeninplainvw6]

This video great.. explains a complicated subject very well

[cawker1984]

Great video. Thank you for explaining everything and not skipping steps. It was extremely clear :)