4.6 Reason For Second Normal Form 2NF
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- Опубліковано 10 тра 2018
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"Jo neta bnna Chah RHA h use bnne do ya to uski galat fami door ho jaayegi ya hmari"😂😂........nice sense of humour sir.
5:28 you can find this
You are one of the favorite tutors I have found on youtube.
Sir aapka neta waala tareeka ek no. h turant samazh me aagya😇
jab kisika nahi samja rdbms tab aap kam aaye sir, wonderfully teacher.
Best teacher of dbms i hv ever seen
Very nice video sir , very helpful , your teaching technique is best
Thank you so much sir for your all videos because of only your video my all concept gets clear
Easy way ...
Very helpful vedio sir..👍👍👍
Sir u r my favorite teacher thank u so much for the videos it's a very helpful
You are doing god's work. Thanks
Sir, the table you have given is having is showing functional dependency of AB -> C; C-->B along with B --> C, but the schema we discussed is showing only B--> C. The table is not showing as suitable example for the schema you drawn. Please explain and correct me with this issue.
Can there be same value multiple times in R1 table? The value C3 appears twice there.
Thank you sir for these videos
Nice lectures sir, this helped me to solve my assignment..... Good work
KHA HO TME AJKAL
namaste sir, vidya daan dene ke liye mera dhanyawad sweekar kijiye.
excellent sir,superb
thank u so much sir!
Sir, I just love the way you teach us....really appreciable.....I have learned so many things from your videos.....thank you❤
I have a doubt in this video..if you kindly tell me then it would be helpful for me..We know what is the problem if a table is not in 2NF and how to translate a table into 2NF....here, in the relation R AB is a candidate key..so both the key's value cannot be null..but individually can so....so if B has one null value in relation R and if we even do decompose the relation R into R1 and R2 then in the relation R2 there may be the null value of B because we are putting the same data from relation R to relation R2....So, how B individually can find C?
Candidate key cannot be null. So there won't be any null value of B in R2.
Very informative
Thank you so much sir
gajab ka banda hai yrr
sir plz bring MCQ series for NTA NET cs...on all topics..specially PYQs
Sir, here A, B is a set of prime attribute so only unique values are allowed but you have taken a duplicate values
Thanks sir g
suppose B ka koi value null hai then hum is case me table kaise decompose krenge.. agar kiye bhi toh us case b us table ka candidate key hoga aur jo ki null nhi ho skta toh fir ye 2nf me bhi toh kam nhi karega na!!
Plz correct me if I am wrong..
Thank u so much sir 😇😇😇
Sir please do an video on lossy and lossless decomposition in DBMS
Thank you sir
Thanks sir ji😆
at 9:08 if B will null, Then we can't find C. So What is solution for that? or Both A & B must not be null is the only solution ? Please comment
thanks sir
I have a doubt please answer..at 2:12...you make AB as candidate key..but we can make A alone a candidate key..whereas B to C is given then also we can find all attributes ABC.. can't we make A alone as candidate key? please reply sir..
Excellent
Is relation key is related to partial dependency
OP sir .....ya to uski galat fehmi dur ho jaegi ya humari 😂😂
U r great sir
Thanks sir 🙏
Sir how u can find the particular column is partial attribute or nonpartial Attribute,
its too long time answer it. but, after watch this video i get some points. i just want to answer this questions. i think you must identify the candidate or primary key and non primary key. and then find the composite key and part of key. if a attribute dependencies from one or part of composite key but not both it means the attribute is the partial dependencies.
1. Find the key
2. Find the prime and non-prime attributes(The attributes which form the key are called prime attributes and the attributes which do not form the part of the key are called non-prime attributes)
3. Find the partial dependencies
ha sir aise hi hindi me hi continue rakhiye aane wali sabhi playlist series 😁
thanku sir :)
U r awsm! sir
Thanks sir 😄
Most welcome Pranjal.. Keep learning and supporting !! Do visit our website www.knowledgegate.in for more courses & contents !!
B bn gye neta 🤣🤣🤣🤣
BTW nice explanation 😊
great teacher❤️
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computer graphics, data comm, object oriented k videos bhi mil jaaye to sem nikl jaayega
Pls upload complex examples soon
Nice
Love you sir
#great
Can candidate key have multiple null values?
Sir, I didn't quite get the last explanation. That agr ye ni krte to B beech mei kahi bhi Null ho jaate. Can you please explain?
Nikita Rawat :: For this, watch the video just before this one.
Sir, is prime attribute -->prime attribute a partial dependency ??
Please reply
Thanks.
that is something related to bcnf.
This is not partial dependency. As per your question, the FD will be in 3NF
B to bahut chalaak nikla neta bann k party bana li apni C k saath..😄🙂.. good explanation sir g
Sir again a doubt here would you plz explain this. To justify the partial dependency problem, you said that if AB is the candidate key and C depends only on B, then if B is null, C would be undeterminable even though AB is not null. That's why we need to decompose the table, but if it were truly to happen as you show in the next step then, for 1st table we have AB with AB as the candidate key and B as the candidate key in the second table. Here B cannot a key because it might be null and that's why we did the decomposition in the initial stage.
Dear Kaustabh, In a relation, if a non-prime attribute is dependent on only part of a candidate key, it is called a partial dependency. This can cause redundancy and inconsistency in the data. To bring the relation to 2NF, we need to remove any partial dependencies by decomposing the relation into two or more relations.
In the example you mentioned, if AB is the candidate key and C depends only on B (a proper subset of the candidate key), then there is a partial dependency. To remove this partial dependency, we can decompose the relation into two relations: one with AB as the candidate key and the other with B as the candidate key. In the second relation, B can be a candidate key because it determines the value of C.
The fact that B might be null is not relevant to whether or not it can be a candidate key. A candidate key is a minimal set of attributes that uniquely identifies each tuple in a relation. Whether or not an attribute can be null depends on the constraints defined for that attribute.
@@KNOWLEDGEGATE_kg got it sir, I actually considered that candidate key cannot be null as an underlying constraint which is not true. Thanks a lot sir.
maja aa gaya sir
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from column A a gives 1 in coumn B and also a gives 3 how is it possible?
it is possible beacause A is not a key itself but only a part of candidate key AB so AB combined needs to be unique.
I the examle functinal dependencies is only given b->c according this no one is super key so no candidate key but how can you assume ab without any dependencies.
A candidate key is ofcourse formed, ie AB.
A is essential attribute..... So we must include it in candidate key
sir please upload i english It will helpful to all students
R1 wale table Mei (ABC) ayega na, why only R1(AB)
R1 mein ABC ni aayega kuki usse redundancy hogi.. 2NF mein decompose krne pr AB k pass bs AB reh gya toh un 2no ko likha h baaki R2 mein B aur C ki different table bna di. Ek baar isse pichli video dobara dekhlo smjh aa jaayega
can you please help me out with R(ABCD) AB->CD ,D->A check 2NF
Dear @Nirjhar, 2NF requires that a relation be in 1NF and that there are no partial dependencies. A partial dependency occurs when a non-prime attribute is dependent on a proper subset of a candidate key.
In this case, the candidate key for the relation R(ABCD) is AB, since AB->CD determines all other attributes in the relation. Since D->A, we can see that attribute A is dependent on D, which is not a candidate key and is only part of the candidate key AB. This means that there is a partial dependency in the relation.
Therefore, the relation R(ABCD) with functional dependencies AB->CD and D->A is not in 2NF.
Everything is fine... But if you explain with some real-time example that could be more helpful...
Masst
Better than Gate smashers!
Sir, Please make a complete Series on solving the previous year GATE Questions Paper
Sir, i think better if you using english full. it makes more people understand easily
Candidate key may be null??
AC-------->B has functional dependency.
Seriously?
B ban gaya neta.....😄😄
Whaa sir
B bhai sahab ban gya neta rajat kumawat😅😅😅
Sir what if B is null. Then how will we decompose table
B cannot be null because after on the position of Neta it becomes Candidate key(PK).. which cannot be null
AB is not a candidate key in this, because they are not uniquely identify. Check row no 4th and 6th. And If I am wrong do correct me.
6th row is 'e' and not c
What will do if we have 3 ->w in R2?
It doesn't matter , you'll just have to replace z with w to get rid of redundancy
B agr bol raha h ki wo c ko fetch kr lega mtlb kr lega iska mtlb wo kbhi null nhi hoga. Moral of the story ye h ki hum jabardasti suppose kr rahe h ki b null ho jaega
where is 4nf?
im confused....the title is in engilsh, but watching the video in a totally different language...even then I was still able to understand, but it just threw me off..
Gzb
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can't find 3rd normal form
sir can you share your email address. i need to know about euler graph`s application.
with respect sir, why do you upload the videos in 480p only..
// P.S. - Great fan of your teaching , would surely like to meet you one day :-)
can't find 3NF
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hi sir
Sir
9:19 ye jo neta the B agar wo kahin bhatak jate aur ban jate null to hum C ko kaise find karte hai.. 😂😂
Sir please explain in english. Difficult to understand in hindi
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how can AB derives C? A is not Candidate key
A in itself is not a candidate key, but AB is. This is because A and B both did not have any incoming edges, that means they surely have to be included in the candidate key.
A.C mangra h purty
b ban gaye neta aur election me har gaye
B hamesha Neta banta h
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Fir bhi Modi hee jitega BTW awesome lecture sir
Thanks sir ji
Thanks sir
Thanks a lot Sir
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