Which of the following is false ?
Every binary relation is never be in BCNF.
A relation is in BCNF if, for every non-trivial FD X → Y that holds, X is a superkey.
Binary relation R(A, B): the only possible non-trivial FDs are A → B and B → A. If A → B holds, A determines both attributes and is a key; likewise for B → A. With no non-trivial FD, AB is the key. So every relation with two attributes is always in BCNF, and the claim that it is never in BCNF is false.
Every BCNF relation is in 3NF: the BCNF condition (X a superkey) is stricter than the 3NF condition (X a superkey or Y prime), so this is true.
1NF, 2NF, 3NF and BCNF are all defined using functional dependencies (and the keys derived from them), whereas 4NF and 5NF use MVDs and JDs, so this is true.
An MVD X →→ Y in R is exactly the binary join dependency *(XY, X(R − Y)), i.e. a JD with two components, so an MVD is a special case of a JD; true.
Hence, the answer is Every binary relation is never be in BCNF..
Similar Questions
The Relation
Vendor Order (V_no, V_ord_no, V_name, Qty_sup, unit_price)
is in 2NF because :
Select the ‘False’ statement from the following statements about Normal Forms :
Consider the schema
R = {S, T, U, V}
and the dependencies
S → T, T → U, U → V and V → S
If R = (\(R_{1}\) and \(R_{2}\)) be a decomposition such that \(R_{1} \cap R_{2} = \phi\) then the decomposition is
Consider the following relational schemas for a library database :
Book (Title, Author, Catalog_no, Publisher, Year, Price)
Collection(Title, Author, Catalog_no)
with the following functional dependencies :
I. Title, Author → Catalog_no
II. Catalog_no → Title, Author, Publisher, Year
III. Publisher, Title, Year → Price
Assume (Author, Title) is the key for both schemas. Which one of the following is true ?
Which of the following statements is false ?
In a schema R(A, B, C, D, E, F, G, H), each field of R contains only atomic values.
F = {CH→G, A→BC, B→CFH, E→A, F→EG} is a set of functional dependencies so that F+ is exactly the set of FDs that holds R. The relation R is :
Which of the following relations can not be decomposed in to BCNF with a lossless join and dependency-preserving decomposition ?
Which of the following/s is/are FALSE statement?
A. An all key relation is always in BCNF since it has no FDs.
B. A relation that is not in 4NF due to nontrivial MVD must be decomposed to convert it into a set of relations in 4NF.
C. The decomposition removes the redundancy by the MVD.
D. 3NF is stronger than BCNF.
Choose the correct answer from the options given below:
Fifth normal form is concerned with :
For a database relation R(A, B, C, D) where the domains of A, B, C and D include only atomic values, only the following functional dependencies and those that can be inferred from them are :
A → C
B → D
The relation R is in _______.
Important Questions from Normal Form
Which of the following statement(s) is/are correct regarding a relation in second normal form?
I. It is in first normal form
II. Every non-key attribute is fully and functionally independent on the primary key
Which of the following normal forms specifically addresses and eliminates partial dependencies?
Consider a relational schema team(name, city, owner), with functional dependencies {name $\to$ city, name $\to$ owner}.
The relation team is decomposed into two relations, t1(name, city) and t2(name, owner). Which of the following statement(s) is/are TRUE?
In a relational database, which one of the following is CORRECT:
The Relation
Vendor Order (V_no, V_ord_no, V_name, Qty_sup, unit_price)
is in 2NF because :
