Materialized Views

1.

Consider a schema R(A, B, C, D) and functional dependencies A -> B and C -> D. Then the decomposition of R into R1 (A, B) and R2(C, D) is

   A.) dependency preserving and lossless join
   B.) lossless join but not dependency preserving
   C.) dependency preserving but not lossless join
   D.) not dependency preserving and not lossless join

Answer: Option 'D'

not dependency preserving and not lossless join

2.

Relation R with an associated set of functional dependencies, F, is decomposed into BCNF. The redundancy (arising out of functional dependencies) in the resulting set of relations is

   A.) Zero
   B.) More than zero but less than that of an equivalent 3NF decomposition
   C.) Proportional to the size of F+
   D.) Indeterminate

Answer: Option 'B'

More than zero but less than that of an equivalent 3NF decomposition

3.

Consider the following functional dependencies in a database.
Date_of_Birth->Age Age->Eligibility
Name->Roll_number Roll_number->Name
Course_number->Course_name Course_number->Instructor
(Roll_number, Course_number)->Grade
The relation (Roll_number, Name, Date_of_birth, Age) is

   A.) In second normal form but not in third normal form
   B.) In third normal form but not in BCNF
   C.) In BCNF
   D.) None of the mentioned

Answer: Option 'D'

None of the mentioned

4.

A table has fields F1, F2, F3, F4, and F5, with the following functional dependencies:
F1->F3
F2->F4
(F1,F2)->F5
in terms of normalization, this table is in

   A.) 1NF
   B.) 2NF
   C.) 3NF
   D.) None of the mentioned

Answer: Option 'A'

1NF

5.

Which one of the following statements about normal forms is FALSE?

   A.) BCNF is stricter than 3NF
   B.) Lossless, dependency-preserving decomposition into 3NF is always possible
   C.) Lossless, dependency-preserving decomposition into BCNF is always possible
   D.) Any relation with two attributes is in BCNF

Answer: Option 'C'

Lossless, dependency-preserving decomposition into BCNF is always possible

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