bcnf normalization in database with example

bcnf in dbms with examples

[ikirstenHD]

I think the decomposition should be = {Std, Course} and {Std, teacher} assuming a teacher is limited to teaching only one course. Your decomposition is lossy. For example, If you JOIN the relations you'll get that Lucky has two teachers. Information is thus lost as a result of your decomposition

[tkrishna]

Agree with Ollie on this. I got confused too with the final decomposition.

[vipulkumarsingh]

course cannot be the super key because the values in it are duplicated

[mrdh]

the best decomposition according to DBMS Book (Elmasry) is {teacher, Course} and {teacher, Student} because it will not generate spurious tuples after a join.

[DhruvParmar-gmke]

This relation is not even in 2NF form. student is determining teacher and student alone is a part of primary key

[rhul]

The example is wrong!!the teacher and course shold be super key because students with same name can enroll the subjects

[GeorgeNavarro]

Shouldn't teacher be a superkey of the table on the right at the end?

[JelloTalks]

Why do your annotation cards come up before you're finished writing stuff down? I can't see the rest

[leeasycode]

Thanks a lot, your tutorials were amazing from 1NF->BCNF....

[sarveshkapoor]

Mam X->Y THEN X shouy be super key but you said {STD, course}->teacher but {STD, course} is already super key

[ramesshnaiidu]

In second table coursename dbms repeted twice...but u said left side should be a super key.

[cyt]

In course and techer table teacher should b super key na ?

[paintedbooks]

what's the difference between primary key and super key at the end tables?

[jeffvarghese]

The decomposition result in loss of data, the best sets are {teacher, course}, {student, teacher} where teacher become the super key in the first table, and student become super key in the second table where teacher will become a referential key

[kailasamkiran]

Mam I have small doubt
Course is super key u r saying but DBMS coming 2 times so there is redundancy
So how it would be super key

[vinaysagarkomarabanda]

Coming to 1NF and BCNF i dont know why Bhanu giving duplicate values for Primary key..

[pallavsadhukhan]

I think it should be {std, teacher} and {teacher, course}

[mk]

X determine y, y must be an candidate key not an supper key..😅mam sahi bola na mene

[Mylikes]

Where is the difference between in 3rd NF and BCNF

[MoinAnsari-sr]

Maam may u know your good name please bcoz if we learn some thing from some we know the name