Lec 7: How to Find Number of Candidate Keys in a Relation - part 1 | DBMS Tutorials
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- Опубліковано 7 вер 2024
- In this lecture, I have discussed a Simple Trick to Find Out all Candidate Keys in a Relation.
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Answer for exercise at 18:31
Number of candidate keys = 4
Set of candidate keys = { AB, CB , AD , CD }
Prime attributes = { A, B, C, D }
Thanks a lot ma'am !! 🤩🎊
This is one of the epic channels to learn DBMS !! Hats off !! 🙌
can you explain it?
@@carishmakhan4694 r(a,b,c,d)
ab->cd , d->b,c->a (prime attribute a,b,c,d)(if prime attribute is on the left arrow side, u can replace it with a new attribute)
ck?
abcd=(abcd)
abd=(abcd)
ab=(abcd) ->ck
(c->a so cb is sk but not sure bout ck)
cb=(abcd)-> ck
(d->b so ad is sk but not sure bout ck)
ad=(abcd) -> ck
(ab->cd so cd is sk but not sure bout ck)
cd=(abcd)-> ck
@@dsadsa5447
How does ad->c?
what I know is that you can only determine c using ab by applying decomposition rule. a alone can not determine c.
@@manytuch i think, AD->B after that we can use AB->CD to get C
@@rishabhsharma3022
Sure, I figured that out after watching the next video. Thanks
These lectures have been filling in all the information that is missing in the text books. Thank you so much!
Thank you jenny for such awesome videos...The thing that separate u from rest of the teachers is that you explain every concept with an example...and I'm a person who looks to knowledge for acquiring skill and making something from that skill rather than to just pass exams ....Thank's a lot for making such informative videos
After watching several videos, not getting clear such concepts, but you make it so simple to understand. thank you so much.
If this type of teacher will be available in India then all peoples will not have to learn like copy from book or Google then paste in exam nd also never forget any topics.... 😊 Thank you ma'm...
Exactly..
AM TITUS from Ghana i have been watching your videos on data structure which is really helpful to me .God bless you .Thank you.
Absolutely Brilliant. There is no doubt you are the best instructor on UA-cam. I have checked out quite a few videos but none have been able to explain this core concept as clearly as you have.
i dont know why u didnt start this series three month ago, coz i really wanted it in my last semester. I m from pakistan and i always watch your videos to clear concepts because u r much better than my lecturer ...... ->Brilliant teacher
Your videos helped me in cracking GATE. Thank You so much mam.
Whats is GATE?
Answer for last question to cross check!!
got AB,CB,CD,AD.
Yes
@@dineshtelangi3233 how AD?
@@essentialsATAesthetics D is determining B.... in place of B we can use D
somebody award this playlist!
How we got CD as candidate key:
we are given that C-> A and D->B, now by the help of Composition rule CD -> AB, thus AB is replaced with CD.
** Composition Rule of Armstrong's Axioms.
D->B does not stands a valid FD for the given Schema. However, BD->B stands valid[by IR1 Reflexivity property]. Your opinion would be correct iff and only if we were pre-provided with the FD D->B. However, this is not the case.
The best course for competitive examination in Brazil cannot pass a subject at its level. Congratulations.
😍 Mam, I got Ck{ AB, CD, AB, CB } as the Candidate keys
I can't explain my word.. To say thank you.. But Thank you so much mem for your efforts to the students... 🙏💝❤
You are the teacher. I can understand very clearly of finding candidate key😻. Before I really confused of it.😭 Thank u so much my lovely teacher. ❤
Prime attributes - A,B,C,D
Ck - AB,AD,CB,CD
I've came to the same solution. So, is this correct?
AB,CB,AD,BD
@@fitnessgurl1396 BD is not even a super key. 🤣🤣
how can you please explain
how bc is termed as candidate key
mine toh only three is there AB AD AC
After watching this video first time,
"Kitni awesome hain yaar.. "
🥰🥰🥰🥰🥰
Bhai thodi padhai bhi kar leta
Thank you mam , you are such an inspiration for all of us who are preparing for GATE
All the lecture in English Just The word "Ayaa Button" :)
Very informational videos ever i seen :)
Your teaching method is best and easy to understand you are really a genius. ❤❤❤
Thank you so much mam really superb video 💫👌
I got AB, AD, CB, CD as candidate keys.
I got the same.
Yeah, I got these too.
I got these same
Explanation [Kindly correct If I'm wrong] @18:24
Ans. 4 - AB, CB, CD, AD
1. [ABCD]+ = {A,B,C,D} -> Super Key. But not candidate Key
Using, C->A, D->B, We simplify 1 as [ABAB]+ which is nothing but [AB]+
Now, [AB]+ = {A,B,C,D} -> Super key.
To check if [AB] is a candidate key,
[A]+ = {A}, [B]+ = {B} which are not super keys. So, AB is a CK
Also, Prime Attributes are {A,B} which is on the RHS of C->A and D->B.
So, the next possible super keys which we have to check as candidate keys are
Replace A with C, B with D and also AB with CD . Results are CB,CD,AD
[CB]+ -> super key. [C]+ = {C,A}. [B]+ = {B} which are not super keys => CB is a candidate key.
[CD]+ -> super key. [C]+ = {C,A}. [D]+ = {D,B} which are not super keys => CD is a candidate key.
[AD]+ -> super key. [A]+ = {A}. [D]+ = {D,B} which are not super keys => AD is a candidate key.
@@bense_tony nice work
Thank a lot . 4 candidate key . ck = {AB,ADBC,CD}
Plz bro explain how
Ans. Of hw question is
CK={AB, BC, AD, CD}
Prime Attributes are
A,B,C,D
AMAZING LECTURE ❤
@@mq4950 plz can u explain how?
My question is solved after watching this video 😊
Thank You Soo much mam
Its remember my maths teacher. U give tough portion as assignment 😁
Super Explanation... Very Very Thankx Maam...👌👌
your way of explanation is too good...MAM
you are a lifesaver, thanks for making such wonderful videos,
Really Your Technique of Teaching is Awesome.Your Viodeos are Really Helpful and understandable. Thank you Mam. You Make My Understanding About Candidate Key.
simply amazing. better than my professor.
Thanks for your technique on finding the candidate keys. It's very very reliable compared to what I was taught in class.
Please add english subtitle so that we(people who not having a very good listening skill) can understand you completely , thanks for well explained video though.
She's trying to teach in english,not her native language.so cooperate u moron.Instead of doing sarcasm....
@@SanjeevKumar-yt7sn I don't think it is sarcasm, if you are not used to one type of accent it can be difficult to understand sometimes. Anyway, awesome lectures
Hi ...myself mtech graduate ,,, your classes are amazing
Got it ma'am AB,CB,CD,AD
PA-A,B,C,D
4 candidate keys possible- AB, CB, CD, AD
I think you're wrong there.
How can you find 'AD' please explain, I didn't understand this
Ck-4
AB,CD,AD,BC
PRIME ATTRIBUTES-{A,B,C,D}
Dhar
Hiii
How can you find
maam u are great , i like ur all videos,ur lactures help me a lot. thanku a lot
Normalise watching Jenny ma'am's lectures in 1.5x 😅
Hi jenny, can you please make a short video explaining the answer of the last question for us? I just wanted to confirm the procedure. Thanks
Bunch of thanks for the clear explanation🧡🧡
Thank you ma'am 😊
3 candidate keys AB,CD and AD all are prime attributes
BC will also be a candidate key
@@alphonseprakash7459 what BC can determine bro is it giving the whole relation then definitely it is if not it is not
BC also will give whole relation
@@viplovekadre9371 yes bro find CB closure u get CD and C->A and B->D hence CB-> CDAB which contains all keys
Lots of thanks for this awesome explanation😊
Mam,can u pls post the solution video for the last question as I have some doubts
Yes, the last question is harder than the solved questions😂😂
you have taught very well but it is very complex
Candidate Keys are :AB,CD,AD,CD Prime Attributes are : A,B,C,D
Thank you very much mam, after watching so many videos, this found to be very informative
Candidate keys: 2 (CD, AB)
Prime attributes: 4 (C,D,A,B)
CANDIDATE KEYS : 3 (AB, AD,CB,CD)
PRIME ATTR. : 4 (A,B,C,D)
Yes i also got the same
If I get three teachers personally 24×7, Code With Harry, Gate Smashers and Jenny
. I will crack Google surely.
CANDIDATE KEY : AB,AD,BC,CD
PRIME ATTRIBUTE : A,B,C,D
How can AD be candidate key plz explain
@@manishpritmani same doubt
@@manishpritmani proper subset of AD are A and D ,whose closure are not superkey ,therefore it is candidate key.
3 candidate keys are present in my point of view
chaa
Amazing ma'am ☺️...i understand all the things... thank you so much ma'am ☺️🥳
I got CD, AB, AD & CB as candidate keys.
Same brother what about the answer is this right or wrong
we can get only 3 candidates keys how we can get 4
My favourite lectures and my favourite madam 😘😘 love you mam you are so beautiful but you didn't smile please smile mam 😅😅😅😝😬 👍👍👍
Mam could you please upload some videos related with database query . It will also be really helpful.
thank you mam, clear concept :)
Thank you very much ma'am . you are very kind . Thank you :)
Thanku so much ma’am for these lectures 🙂
Very helpful, thank you very much
The explanation is very clear and easy to understand. Thanks.
Can you please solve this: how many candidate keys are there in the given relation R. R(A,B,C,D,E) and functional dependencies are
A->BC ,CD->E, B->D,E->A
PRIME ATTRIBUTES- A,B,C,D
CANDIDATE KEYS- { AB, CB, CD }
why can't AD be a candidate key?
@@pittavivekreddy5022 ad also
@@155.p.vijayaraju5 actually i knew that, am actually questioning her, i intend to let her know the mistake she has done
@@vivekreddy7315 please tell how ad is candidate key
please can you give the clear explanation?
wtf this person is awesome thank u :)
You are a darling... Thank you so much!
Please numbered each video with1 2 and 3 in play list it will become more organise .
AB, CD ARE the final candidate keys I got mam.
Yes,I got the same
Thank you MA'AM for such awesome video 🙌
AB, AD, BC, CD and all prime attributes
Can u pls tell me where u got that BC cuz I only have AB, AD, CD
@@altinarexha6134 CB from AB as C->A
@@altinarexha6134 I too got 3 composite keys ....I didn't get bc
@@anuragsoni1840 cd comes from c->a
Miss please do all videos in English because as ure thinking the whole world should benefit from your videos. For example u had done diwali video in hindi. I couldn't understand dear mam
U r best teacher thank u mam🙏
Thanku maam 😘
Thank You Mam❤!
Hi mam.. as a kind request... Pls make some videos on python programming language....
thanks for uploading candidate key .............
very helpfully video thank you mam
Much love from UTCN
Thanks for this mam !!
In the 2nd example when you used transitivity theory to say that since A determines B and B determines C, A then eventually determines C. Isn't this wrong since in the next functional dependancy you have mentioned (in the curly braces) that A depends on C? Shouldn't the transitivity be applicable only if A doesn't depend on either B or C?
SO now you got the answer ??if you get than tell me also
I kinda felt same... Yeah mam did a mistake their....
@@manishjarodia2561 hii hope you figured it out by now. Excuse me for not replying soon.
@@maheshiyatipansalawa4014
Jenny Mam....Really u r awesome to explain complex concept in understandable way....Really thanks to u.....
AB,AC,AD,CB,CD are the candidate keys for the last question
it is wrong answer
Nice video mam always give proper solutions
Candidate Key :- AB, CB, CD, AD
Prime Attributes :- {A,B,C,D}
This answer I've got..
bhai answer bhejna
tnk u..
answer for the last question is No. of candidate keys are 4
those are={CD,AB,CB,AD}
for R(A,B,C,D,E) {A,B,C,D,E} will only be a SuperKey IF the table does not have duplicate rows right?
so for such a table how do you go about determining the maximal SK ?
Thanks for the lecture...and the answers is 3( C.K )which are AB,CB,CD and prime attributes are (A,B,C,D ). Correct my answer plz..
yes bro you it's true
Thank you
I know this concept well. even then I am watching it because of you only mam...
stop reading comments and focus on study........
hello bro....ans for questions asked by her will be seen in comment section .so that many will see comment section for that purpose.
@@tejaswigopaladasu7372 ok ok...
@@harshadlokare terer jaise hi jobless hote hein
@harshad lokare Stop commenting and focus xD...
CK :- AB,AD,CB,CD Prime attribute :- (A,B,C,D).
4 CK:-{CD,AB,CB,AD}
Prime Attributes:-{A,B,C,D}
AD kaise aayega??
Super
Mam great explanation ☺️
AB,AD,CB,CD are candidate keys
Please explain how you got 4 candidate keys?
@@thalathalapathy6463 AB
AD
CD
CA
Thanks mam
Allah ape ko buhat kamyabi day
I found 4(AB,AD,CB,CD) candidate keys in this relation
Good one👌👌👌👌👌