1
GATE CSE 2008
MCQ (Single Correct Answer)
+2
-0.6
Let $$R\left( {A,B,C,D} \right)$$ be a relational schema with the following functional dependencies:
$$A \to B,\,\,B \to C,\,\,C \to D$$ and $$D \to B.$$
The decomposition of $$R$$ into $$(A,B), (B,C)$$ and $$(B,D)$$
A
gives a lossless join, and is dependency preserving
B
gives a lossless join, but is not dependency preserving.
C
does not give a lossless join, but is dependency preserving
D
does not give a lossless join and is not dependency preserving
2
GATE CSE 2008
MCQ (Single Correct Answer)
+2
-0.6
Let $$R\left( {A,\,B,\,C,\,D,E,P,G} \right)$$ be a relational schema in which the following functional dependencies are known to hold: $$AB \to CD,\,\,DE \to P,\,\,C \to E.\,\,P \to C$$ and $$B \to G.$$ The relational schema $$R$$ is
A
In $$BCNF$$
B
In $$3NF,$$ but not in $$3NF$$
C
In $$2NF,$$ but not in $$3NF$$
D
Not in $$2NF$$
3
GATE CSE 2007
MCQ (Single Correct Answer)
+2
-0.6
Which one of the following statements if FALSE?
A
Any relation with two attributes is in $$BCNF.$$
B
A relation in which every key has only one attribute is in $$2NF$$.
C
A prime attribute can be transitively dependent on a key in a $$3$$ $$N$$F relation.
D
A prime attribute can be transitively dependent on a key in a $$BCNF$$ relation.
4
GATE CSE 2006
MCQ (Single Correct Answer)
+2
-0.6
Consider the relation enrolled (student, course) in which (student, course ) is the primary key, and the relation Paid (student, amount) where student is the primary key. Assume no null values and no foreign keys or integrity constraints. Assume that amounts $$6000, 7000, 8000,9000$$ and $$10000$$ were each paid by $$20$$% of the students. Consider these query plans (Plan $$1$$ on left, Plan $$2$$ on right) to ''List all courses taken by students who have paid more than $$x''$$. GATE CSE 2006 Database Management System - Functional Dependencies and Normalization Question 20 English 1 GATE CSE 2006 Database Management System - Functional Dependencies and Normalization Question 20 English 2

A disk seek takes $$4ms$$, disk data transfer bandwidth is $$300MB/s$$ and checking a tuple to see if amount is greater than $$x$$ takes $$10\mu s.$$ Which of the following statements is correct?

A
Plan $$1$$ and Plan $$2$$ will not output identical row sets for all databases
B
A course may be listed more than once in the output of plan $$1$$ for some databases
C
For $$x=5000,$$ Plan $$1$$ executes faster than plan $$2$$ for all databases
D
For $$x=9000,$$ Plan $$1$$ executes slower than plan $$2$$ for all databases
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