Lec 7: How to Find Number of Candidate Keys in a Relation - part 1 | DBMS Tutorials
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- Опубліковано 8 лют 2025
- In this lecture, I have discussed a Simple Trick to Find Out all Candidate Keys in a Relation.
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#howtofindcandidatekeyinarelation
#candidatekey
#DBMS
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Stuying computer sience in germany and i gotta say this is the best playlist for DBMS
same 👏👍
She is the best.
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.
The best course for competitive examination in Brazil cannot pass a subject at its level. Congratulations.
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.
AM TITUS from Ghana i have been watching your videos on data structure which is really helpful to me .God bless you .Thank you.
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..
somebody award this playlist!
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?
@@cmmsilva gate is nothing but a iron gate in front of home 🤣🤣... competitive exam man
Normalise watching Jenny ma'am's lectures in 1.5x 😅
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
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.
All the lecture in English Just The word "Ayaa Button" :)
Very informational videos ever i seen :)
Thank you mam , you are such an inspiration for all of us who are preparing for GATE
I can't explain my word.. To say thank you.. But Thank you so much mem for your efforts to the students... 🙏💝❤
Your teaching method is best and easy to understand you are really a genius. ❤❤❤
Answer for last question to cross check!!
got AB,CB,CD,AD.
Yes
@@dineshtelangi how AD?
@@essentialsATAesthetics D is determining B.... in place of B we can use D
got the same
After watching this video first time,
"Kitni awesome hain yaar.. "
🥰🥰🥰🥰🥰
Bhai thodi padhai bhi kar leta
Candidate Keys are :AB,CD,AD,CD Prime Attributes are : A,B,C,D
Great video and excellent explanation! Thank you, J
your way of explanation is too good...MAM
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?
Really Your Technique of Teaching is Awesome.Your Viodeos are Really Helpful and understandable. Thank you Mam. You Make My Understanding About Candidate Key.
thank u mam! u made this super easy
My question is solved after watching this video 😊
you are a lifesaver, thanks for making such wonderful videos,
Thank you so much mam really superb video 💫👌
Super Explanation... Very Very Thankx Maam...👌👌
Thank a lot . 4 candidate key . ck = {AB,ADBC,CD}
Plz bro explain how
simply amazing. better than my professor.
you have taught very well but it is very complex
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
Bunch of thanks for the clear explanation🧡🧡
Its remember my maths teacher. U give tough portion as assignment 😁
Got it ma'am AB,CB,CD,AD
PA-A,B,C,D
maam u are great , i like ur all videos,ur lactures help me a lot. thanku a lot
Thank you ma'am 😊
Thanks for your technique on finding the candidate keys. It's very very reliable compared to what I was taught in class.
Very helpful, thank you very much
Answer for question at 18:31 :
Number of candidate keys = 4
Set of candidate keys = { AB, CB , AD , CD }
Prime attributes = { A, B, C, D }
thanks mam . It helps me a lot :)
The explanation is very clear and easy to understand. Thanks.
Ck-4
AB,CD,AD,BC
PRIME ATTRIBUTES-{A,B,C,D}
Dhar
Hiii
How can you find
Hi ...myself mtech graduate ,,, your classes are amazing
Thank You Soo much mam
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.
Really really such a wonderful video ma'am. Thanks a lot
Thank you very much mam, after watching so many videos, this found to be very informative
wtf this person is awesome thank u :)
U r best teacher thank u mam🙏
Amazing ma'am ☺️...i understand all the things... thank you so much ma'am ☺️🥳
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
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
Thank you very much ma'am . you are very kind . Thank you :)
You are a darling... Thank you so much!
Thank You Mam❤!
thank you mam, clear concept :)
Thank you MA'AM for such awesome video 🙌
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
Thanks for this mam !!
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?
very helpfull
Sometimes you use commas and other time you don't when expressing the sets. For example you expressed in this video for the closure of ABCDE = {A,B,C,D,E}, in other videos it was ={ABCDE}. Which one is the correct way? Or does it matter? I see the same thing my professor doing when working through problems and it confuses me when providing answers on exams and homework. Thanks in advance.
Thanku so much ma’am for these lectures 🙂
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
very helpfully video thank you mam
CK :- AB,AD,CB,CD Prime attribute :- (A,B,C,D).
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
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😂😂
4 CK:-{CD,AB,CB,AD}
Prime Attributes:-{A,B,C,D}
AD kaise aayega??
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
Thank you
My favourite lectures and my favourite madam 😘😘 love you mam you are so beautiful but you didn't smile please smile mam 😅😅😅😝😬 👍👍👍
Candidate Key :- AB, CB, CD, AD
Prime Attributes :- {A,B,C,D}
This answer I've got..
bhai answer bhejna
3 candidate keys are present in my point of view
chaa
13:30 is [DA]+ , [DB]+ , [DC]+ also is the candidate key instate of only [DA]+ ?
❤❤❤
Mam please check the vedio @6:45 where AD+ is super key. you just skip it.
thanks for uploading candidate key .............
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
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
I can not decide how AD is candidate key. Actually by replacing derterminant it is clear AD is SK but i can not figure out how its closure is containg all the attribute.
This is what i am doing
Given FD: AB->CD, D->B, C->A
from above given fd i have done this
AB->C, AB->D, CD->AB, CD->A, CD->B,
D->B
AD->AB
AD->A
AD->B
Using above given and calculated fd I could only idententify A, B, D attributes in the closure set of AD
I want someone help me how AD is SK
And rest i can figure out myself
I apprepriate you invaluable help.
Thanku maam 😘
Much love from UTCN
Mam could you please upload some videos related with database query . It will also be really helpful.
Nice video mam always give proper solutions
If I get three teachers personally 24×7, Code With Harry, Gate Smashers and Jenny
. I will crack Google surely.
Jenny Mam....Really u r awesome to explain complex concept in understandable way....Really thanks to u.....
Mam great explanation ☺️
AB, AD, CB, CD are Primary key and also Candidate key
Prime attributes are {A,B,C,D}
Please explain how you got candidate key
I got only two candidate key
Candidate key is a key whose subset is not a super key
Like in AB
Subset is {A,B}
Here A+ ≠ All attributes
Or
B+ ≠ All attributes
So A or B is not super key
Please numbered each video with1 2 and 3 in play list it will become more organise .
Excellent mam
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
Good one👌👌👌👌👌
16:50 B+={B,C,A,B} so B is a superkey . But she told B is not Superkey . Can anyone explain?
tnk u..