CS4604 Final Examination
December 13, 2005
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Question
Maximum Score
Score
1
30
2
15
3
15
4
25
5
15
6
*
20
Total
100
*
Extra credit
1
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(a) If relation
R
has
n
tuples and relation
S
has
m
tuples, what is the maximum number of tuples
that
R

S
can contain? Assume settheoretic semantics.
(b) Convert the relational algebra expression
R
∩
S
into SQL, with the constraint that the RDMBS you
are using does not support the SQL commands
INTERSECT
and
EXCEPT
. You may use commands
such as
IN
,
EXISTS
, and
NOT
, if you need to.
(c) If you are converting an E/R diagram to ODL, what must you ﬁrst do to multiway relationships?
(d) How many nontrivial multivalued dependencies are possible in a three attribute relation?
(e) Circle all the sentences that are true:
(i) 4NF implies BCNF.
(ii) 4NF implies 3NF.
(iii) 3NF implies 4NF.
(f) What is the diﬀerence between the natural join
R ./ S
and the thetajoin
R
./
C S
, where
C
is the
condition that
R±A
=
S±A
for each attribute
A
that appears in the schemas of both
R
and
S
?
(g) List three policies for maintaining referential integrity in a database.
(h) Circle the correct answer. An RDBMS stores and manipulates relations using set/bag semantics.
(i) Circle
True
or
False
. The relation
IsParent(Child, Parent)
stores childparent pairs. Since
we have not yet invented timetravel, let us assume that this relation cannot contain cycles, i.e.,
there is no sequence of two or more tuples such that the parent in the ﬁrst tuple is the child in
the second tuple, the parent in the second tuple is the child in the third tuple, and so on, and the
parent in the last tuple is the child in the ﬁrst tuple. Based on what we learnt in class, we can
write a single SQL query, which may include subqueries, to check if
IsParent
contains cycles.
(j) Name any movie, book, or comic strip, or TV series alluded to in this exam.
2
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 Fall '08
 CMMALIK
 Relational model, SQL Query, E/R Diagram

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