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Questions tagged [bcnf]

Boyce–Codd normal form (or BCNF or 3.5NF) is a normal form used in database normalisation.

Boyce–Codd normal form (or BCNF or 3.5NF) is a normal form used in database normalisation. It is a slightly stronger version of the third normal form (3NF). BCNF was developed in 1974 by Raymond F. Boyce and Edgar F. Codd to address certain types of anomaly not dealt with by 3NF as originally defined.

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What is the difference between 3NF and BCNF?

Can someone please explain the difference between 3NF and BCNF to me? It would be great if you could also provide some examples. Thanks.
cactusboat
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What is a good KISS description of Boyce-Codd normal form?

What is a KISS (Keep it Simple, Stupid) way to remember what Boyce-Codd normal form is and how to take a unnormalized table and BCNF it? Wikipedia's info: not terribly helpful for me.
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Finding a relation in 3NF but not in BCNF

I've been reading many different sources on how to differentiate relations that are in 3NF/BCNF. And I've so far this is my understanding... I will use this relation as an example... R = {A, B, C, D, E} and F = {A -> B, B C - > E, E D ->…
Ogen
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BCNF of a Relation with no FDs

A simple question that I do not seem to find an answer for online: Is the relation that has no non-trivial functional dependencies considered to be in BCNF form and if not, how do I decompose it? Thank you in advance!
Alexander Nenartovich
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BCNF: Looking for example that actually uses superkey instead of candidate key

The definition of the Boyce–Codd normal form states that the determinants of all non-trivial functional dependencies have to be superkeys. All the examples for relations in BCNF I found make use of candidate keys. I am looking for an example that…
starbroken
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Bcnf lossless join

Are all relations in bcnf provide lossless join or can any relation be bcnf but not lossless join at the same tiem? Is there a way to show that a relation that is not in bcnf but NOT lossless join.
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3NF vs BCNF: Example

Gday lads, Ok, so I'm having a database class and I have this example that makes me think that I really didn't fully understand the difference between the two NFs.. I know that A relation, R, is in 3NF iff for every nontrivial FD (X->A)…
geekybedouin
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Boyce-Codd normal form with circular functional dependencies

In relational database design, For example, there is schema S(banker, bname, customer) and function dependencies (FDs) banker->bname customer,bname->banker Is schema S in BCNF? Or it should be: (banker, bname) and (customer, banker)
Alfred Zhong
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What is the minimal proof that a database relation is not in BCNF?

I have the following functional dependencies (they represent all the functional dependencies on my relation): (1) BrokerName -> Office (2) StockName -> Dividend (3) InvestorId -> BrokerName (4) InvestorId, Stockname -> Quantity (5) InvestorId,…
ptk
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BCNF and 4NF property

I read a statement "Relation R in BCNF with at-least one simple candidate key is also in 4NF" I don't think that it is always true but I am not able to prove it. Can someone please help ?
Zephyr
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Getting the same FDs you start with after BCNF decomposition?

I did BCNF decomposition on a relation that has 5 functional dependencies and ended up with 5 relations. However, each new relation had the same attributes and FD as one of the original functional dependencies. e.g. one functional dependency was AB…
Alex W
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BCNF, 3NF, and candidate keys

I am having issues understanding how to determine if relations are in BCNF, 3NF, and in general identifying the candidate keys of a relation. Consider relation R = (A, B, C, D) with the functional dependencies: AB -> C C -> D D -> A The questions…
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BCNF Decomposition and Keys

I've been looking to decompose the following relation from its present state, into BCNF with three functional dependencies. Taking the maxim the key, the whole key, and nothing but the key I concluded that B-->C transitive functional dependency…
davidhood2
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Normalizing & decomposing to BCNF

I've been given the relation and functional dependencies And am looking to justify what form it is in, and then to transform it into BCNF. Now I proposed that it was in 3NF, as the second FD is a transitive dependency with a key attribute as its…
davidhood2
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BCNF Decompositions and Lossless joins for Databases

Hey all I have an assignment that says: Let R(ABCD) be a relation with functional dependencies A → B, C → D, AD → C, BC → A Which of the following is a lossless-join decomposition of R into Boyce-Codd Normal Form (BCNF)? I have been researching…
derp
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