UHCL 27a Graduate Database Course - How to use Functional Dependencies to determine keys

[@Leonn189]

Please give this man an award.

[@tiffanyluo1674]

None of my professors had an answer when we asked for a methodical way to do this. Thank you for sharing and explaining this method!

[@skeptic3045]

My teacher has his script full of algorithms without any clear description or even names for the algorithms..You explain it so easy..Thanks a lot Mr Boetticher..

[@arunimasrivastava5753]

Most accurate method of finding candidate keys and prime attributes. Normalization was never so easy before. Thank you.

[@robosergTV]

getting smarter every video, thanks!

[@ubermons]

This does help a lot. Wish I had a lecturer like you.

[@danielbetter4320]

Thank you Gary. A great, quick and easy-to-understand tutorial with a very cool method.

[@MrGloverDude]

You're like the yoda of databases.... thank you so much

[@insasibleneha]

Thank Gary ! Its a really smart video.. I have been pinning over books to get this straight for days.. its finally done :)

[@cryptofxalgorithms]

splendid teaching Gary ,thumbs up

[@ignatescuadi]

Thx Gary, I might pass the exam tomorrow because of u...:)

[@YKLUO]

the best dbs course i have seen, help me a lot! thx! Prof!

[@Zux78]

Thank you for sharing these excellent videos, Mr. Boetticher! They were more than helpful!

[@atulgangwar081292]

The video also gives you a better understanding. Impressive.

[@FringeOfChaos]

Damn. So glad I found this, it was a perfect explanation of something that's been giving me some trouble.

[@DominoChild]

Sir, your lectures have helped me so much! I wish you were my DBMS professor.

[@somebodypiano6191]

Thank you, I had no idea how to do this and I really needed this video to figure it out!

[@panoramic79]

This was a lot of help for class I'm taking elsewhere. Thanks!

[@whatup7358]

You deserve Turing Award for this

[@Quickslvr311]

Thanks so much for this video. My text book is so incredibly long winded and inappropriate for such a simply understandable concept. You just helped me get 20 points on my final :D

[@GaryBoetticher]

If the left hand side (A closure in this case) is a key, then it is not necessary to try any permutations with the middle group of attributes. If the left hand side is not a key, then you must try combinations with the middle set of attributes.

[@RazikhShaik19]

Made it so damn easy! Thank you so much

[@pornovlaxos]

Great video...helped me solve 1 problem on my databases exams :D

[@eberbachl]

Gary - you sir, are a legend!

[@MtrFadi]

wow .. you make everything easy and simple !! thank you

[@boredalpaca]

Wow, you really made it simple to understand. Thank you so much!

[@GaryBoetticher]

@ThreeLeggedBandit Hi, I am not sure what you gain by identify LHS with no extraneous attributes. Using the LMR approach, you know that the LHS attributes will be part of every key. Middle attributes are added as needed. Best, Dr. Boetticher

[@IvoirRienna]

Easy to understand. Thank you for this great explanation!!!!

[@chaozkreator]

Great explanation! One quick question though, is it necessary that we find ALL the keys for the relation? I know in your 2nd example, "A" closure alone wasn't able to determine any keys, so you had to take the closure of BOTH "AB" AND "AC" to determine the keys. But what if you can already determine a key from just "A" closure? Would you stop there? Or would you also try out the permutation combinations of the attributes in the middle column as well?

[@AshleyJae12]

I'm truly grateful for your help!!! :D

[@shrutiagnihotri8066]

Amazing videos !!!! .. I have one question for you that what will be the candidate key for a relation R(c,s,z) { cs > z, z > c} ....and also what are the prime and non prime attributes ? Thanks

[@Angava]

Thanks. You help me alot for my Data Base finals

[@sagardh4u]

Great explanation. Very helpful. Thanks

[@ANGAYARKANNI_A]

Excellently explained . thanks a lot. If download of this video is available it would be a get help sir. I really love your classes.

[@ferrino_11]

Dr. Boetticher, May I know why is B not a prime attribute? If we take AB+, we get ABC. That makes AB+ a candidate key which leads to A and B being prime attributes.

[@assyriaaaaa]

Very good thank you very much! Keep up the good work PRO!

[@mcgooo1]

Thanks a lot, very good explanation, finally I got it

[@SauravBhattacharyya03]

Thanks a lot. This video tutorial was a big help

[@SafwanNet]

I d appreciat an explanation of Trivial Dependencies I do not think I heard about it in this video or the one on minimization, but I am assuming that it has got something to do with minimization.

[@ryana-6762]

living legend thanks Gary!

[@leenachatterjee12]

Sir will you please also post a lecture on multivalued dependency and 4 NF? I like your way of teaching.A great and useful video.thanks a lot.

[@Mark-tn4xi]

This was very helpful for my databases course. I'd just add that when there is an attribute in the relation that isn't functionally determined, it must be added to the "key(s)" found with the L/M/R method to find the true key (if the second example included an attribute E, but had no additional dependencies). Am I way off base?

[@juanmari9136]

Thanks man, that's exactly what I was looking for

[@jonesrz]

There are many different types of keys, like secondary key as well. Attribute is prime if it is part of the CK (candidate key) and non-prime otherwise, makes a far better definition.

[@GaryBoetticher]

Please see my video where I define what a key is. Search for "UHCL 18A" and go to the 8 minute mark. The definition of "prime" assumes the definition of "key" found in the other video. Best wishes, Dr. B.

[@wenhaoqi9682]

Thank you! Helps a lot.

[@istvanszabo6875]

you are soooo clear; thank you for this video!

[@ramazanc86]

Thank you! Your course is very helpful

[@samiabdullahalayed]

Thank You Very Dr.Gary

[@Diastro3D]

Thank you very much for you very clear example sir. Very helpfull for finals!

[@alextreme98]

Nice video, thanks for the explanation !

[@dennisabraham1289]

Excellent videos . . . .

[@TheRoxas13th]

Question sir, how do we determine which will determine another keys? and which keys depends on the other keys? I kind lost at there =="

[@ashah.nagoriya1496]

Given that R(ABCDE) and set of FD' on R given by F={AB->CD,ABC->E,C->A} IN what normal form? BA+=BACD which is prime only...am i right?

[@brijesh7eq]

Awesome tutorial its very helpful , Thanks sir

[@soldadopreciso]

greetings from Guayaquil, Ecuador. Thanks

[@neilballard1184]

great video. Thanks a lot!

[@NiteshKumar-sd2cz]

thanks a lot gary 😊

[@allend433]

Great video! THANK YOU FOR THIS!!!!

[@mahnazha]

thank you so much. a question.( A B C) can the key also be AB ?

[@wearecode9199]

Very good, so i am guessing if we have an attribute non dependent on anything it automatically becomes a part of key ?

[@rhl_]

Yes true.

[@suparcot]

Well explained but does not cover what IF we have an attribute which IS not a part of any FD. For instance a R has ABCDE and we have various FD with A C D E and leave out B . Then I think B should be a part of the final key along with what comes out of the L/ M / R design. Right ?

[@MrAwesome__]

Supriya Arcot Supriya Arcot exactly what I was wondering after the video, but you answered it perfectly with an example.

[@irvinglee8622]

yea didnt thought this algorithm in class lol !! easy to understand thanks for this video :)

[@vitali450]

hey help please.. i have {abc->d,d->a} left :b,c and middle :ad what are the keys here...? d*=ad; a*=a bc is the key? but it is a wrong....

[@TheRoxas13th]

What it mean by Prime key is candidate key?

[@gigicai310]

So helpful! Thanks a lot!

[@Gavrek]

do you only need to add the middle letters if the left letters are not a key? or do you try every combination anyway?

[@1918santhoshsk]

Awesome Videos

[@valestighi3155]

I love you Gary

[@sanwaysarkar]

thank u sir , helped a lot , u r amazing

[@vitali450]

thank you anusha you was very helpfull!

[@tamoghnapurkayastha8377]

In the second example R(ABCD), what are the candidate keys??

[@yspede0000]

you are a lifesaver :D

[@maxlimgj]

ur the champ gary love u deep deep

[@NehiroHakodate]

thank you, professor

[@chris_tzikas]

How is it that right, left, left produces middle?

[@falven]

THANK YOU SO MUCH!

[@danadeeb6195]

Thank u soooo much. Ur awesome. It is very helpfull...

[@MMoussa4it]

Hi, Could you help me solve this problem, please? R(StudentID,DepartmentID,TutorID,CourseID,EnrollmentDate,StartDate, FinalExam)with the following FDs StudentID, CourseID=>EnrollmentDate DepartmentID=>TutorID DepartmentID, EnrollmentDate=>StartDate StudentID, StartDate=>FinalExam 1. What are the candidate keys of R? 2. Provide a BCNF lossless-join decomposition for R(StudentID,DepartmentID,TutorID,CourseID,EnrollmentDate,StartDate,FinalExam). Show your steps.

[@thesadboxman]

Is there a name for this technique?

[@milenetsi]

Really helpful!! Thanks!!

[@vishnusbabu1]

Thank you sir...

[@piacare]

You are amazing, sir.

[@AlexGonzalez-xd4lg]

Hi.. it is really interesting and was quite helpful. Can you help me with some videos on first, second and third normal form.. would be really grateful if you extend your help.

[@ayushmanmishra8858]

If a relation R(A,B,C,D,E,F) has functional dependencies {AB->C, C->DE, E->AF, F->B},then which one will be the primary key for this relation R?

[@istvanszabo6875]

i might be wrong but C and E seem to be the candidate keys for R (you choose you primary key)

[@AlejandraStamato]

IT HELPS! Thankssssss !!

[@spacepod100]

5:00... how do you know its only A

[@camelCaseFTW]

thanks for the help :D

[@sarfarazsoomro]

thank you!

[@fahimn2472]

THANK YOU!!!!!!!!!!!!!!!!!!!!!!!!!

[@igniculus_]

you are a legend

[@antonijabaric8389]

thank you

[@chemago9938]

thanks Dr

[@ahsan_kamal]

Awesome

[@-7827]

I love you man

[@khairinorizan6797]

Most broski of all the broskis

[@wognild87]

Thank you sir! :)

[@umarsheikhsalem955]

Hahahahahhaaa.. Dude the fast forward part is killing it :v

[@joeetheawesome]

This really helps!!!! :')

[@TejwanshSingh]

How can we determine the candidate key using this procedure. is the key we find the candidate key ???

[@GaryBoetticher]

This procedure finds all candidate keys.

[@Bakugantsuvai1]

+GaryBoetticher Lets suppose I have no attributes in the L side, some in the M side, and others in the R-side, how would I compute the set of Candidate keys from there?

[@garyboetticher9193]

+HimikoWerckmeister Try the powerset of the M attributes.

[@rommoroy033]

please help me to solve this problem sir , A->BC CD->E B->D E->A FIND OUT THE CANDIDATE KEYS....THANK YOU SIR..PLEASE HELP

[@jeevanwijerathna]

thanks