How to perform 3NF Decomposition and BCNF Decomposition?

In this video I go over how to perform 3NF Decomposition and BCNF Decomposition to bring relations into a stable Normal Form.

[@qanda1702]

Hi everyone! Yes you're right, for BCNF at 6:12 it is R-X and XA, not R-A and XA.
I didn't say it correctly, but it is written correctly.
Thank you for everyone that pointed that out! 😊

[@Vwcz]

Well which is it? In your examples, you follow using R-A and XA?

[@lucaceccagnoli2781]

@@Vwcz the correct one is R-A and XA

[@nivedkml]

actually, u said it correctly..but didn't write correctly..

[@coolorphans]

smh

[@owen551]

@@lucaceccagnoli2781 youre the goat

[@evelynsun6774]

the candidate key for first question in 3NF should be ACDF? Since E can be determined by ACD already

[@scorpionedge]

yes she made a mistake apparently

[@pedrosousa7254]

I totally agree with you

[@yummi9954]

thank you, this is excellent explanation! you have a very nice voice and handwriting

[@simoneandriani294]

i know that you didn't pass the exam

[@scorpionedge]

for BCNF its not R-X and XA its R-A and XA.

[@pushanpore422]

exactly thats what I thought for whole ending of the video

[@VAMSIKRISHNA-kr3qf]

At 2.43 the candidate key u have mentioned is wrong it acdf ........ from acd u get e so no e is required....for me the video was good . Thank you

[@eugeneku3239]

pretty voice, best explanation that solved my troubles during past 6 hrs

[@alankotlyar3000]

Thank you! Why is that the candidate key is included among the relations in the first example (2:51) but not in the second (5:50)?

[@yuanheli8566]

Thanks! this is a very clear video.

[@FibrarcadeCrous]

you are a savior

[@mahatma_randy123]

BCNF Decomposition starts at 5:50

[@mohammadalqahtani5673]

Amazing video

[@prandrex1066]

Excuse me but, at 6:45 you say R2(BCD) because it's R-A, but the dependence is D->A so D is our X and R-X is R1(A,B,C) and R2 (A,D) or is it wrong?

[@m.preacher2829]

5:47 why u wrote so many relations? ADFHG includes alrady part of the candidate key(AD)

[@vicentecoopman97]

thank you, it helped me a lot

[@anky_arts]

You're really good at explaining terms,
Can you make similar type of playlists for OOP USING C++ AND RDBMS

[@MrZelektronz]

Why exactly is R2 not in bcnf (7:33)?

[@dropthatbeat7549]

i dunno :(

[@wonglaihim4864]

exist F: D->A but not exist F: D->AB or F: B->AD or F: AB->D ,thus should decompose to D->A, D->B I think

[@MrZelektronz]

@@wonglaihim4864 I won't check now, but thanks :) I finished University last year and am now working as a software engineer and it's probably 4 year ago I last needed to know bcnf but may look into it again

[@shaqtech]

Awesome tutorial, easy to understand!

[@takhminam6068]

Thank you so much!

[@NosamFree]

3:40 why we dont delete AEH -> B hence we already have A->B ?

[@Mrdotcom321]

For the example starting at 2:52, is it possible to get two (or more) different minimal bases?

[@razvanefros411]

you never explain how you check if a sub-schema is in BCNF

[@anivetha2124]

U said R-A but written as R-X

[@areebans]

try not erasing lines(they are usefull too)...great explaination though!!!

[@Jsheng007]

The last example of BCNF, why R4 is in BCNF?

[@qanda1702]

Hi, R4 is in BCNF since both B and D can be reached since both relations start with B and D, and the CK itself is BD

[@ohhhbirdy5975]

I get lost at 1:50, how does abcd equal abcde when it's not anywhere on the right side? I seriously can't understand BCNF for the life of me

[@testusernameyoutube1]

It is ! take a look at the second functional dependency ABCD -> E . With that you can derive E from ABCD alone

[@luigidorigatti4588]

Great video! How do I find the Candidate Keys(ck) once I split the violation into 2 relations? For example at @7:11 where they are -BC and A-? Please answer me I have a test!

[@katesaychaleun6322]

I'm wondering the same! :'(

[@olefinsang2646]

I Think hard to understand for me thou

[@vishnuvardhan6625]

I think BD is not bcnf for the last question

[@Ruiii]

why did u stop posting

[@axela.9247]

You dont explain what BCNF is to begin with

[@sreejithsuresh357]

BCNF is it R-X or R-A????

[@scorpionedge]

R-A and XA.

[@sreekarchintala5535]

A->B, CD->A, CB->D, CE->D, AE->F. This is the minimal FD set and candidate key is CE. Could you please decomposite this into 3nf

[@LukaMladicevic]

bad explanation, too complex for a starter

[@ertugdilek8938]

bunu neden yapıyoruz

[@spencer4329]

This video gives very poor explanations. The reasons for violations are not explained at all and you dont even talk about half the stuff you do.

[@qanda1702]

Hi sam, thanks for the feedback.
I'm sorry my explanation was not thorough enough in this video. I will try to improve for the future. I also have a video "What are Normal Forms in Database Design?" which expands on what causes violations in these normal forms.

[@Jojkata9]

Check what a candidate key is, before making RUclips tutorials.