This preview shows page 1. Sign up to view the full content.
CSC4402 Homework #6
Due Wednesday 11112009
1.
Shown belowisa
relation value (instance)
for the relation
r
(
R
)where the
relation schema
Ris
givenbyR(ABCDE).
Relation value for
r
(
R
)
AB
CDE
A
1
B
1
C
1
D
1
E
1
A
1
B
2
C
1
D
1
E
1
A
2
B
2
C
1
D
2
E
3
A
2
B
3
C
3
D
2
E
2
A
2
B
3
C
3
D
4
E
2
Consider the set of functional dependencies F = {A
→
B, B
→
C, D
→
E, CD
→
E}.
Foreach functional dependency(fd) in F
,determine whether or not this fd is satisfied by this
relation value for
r
(
R
). Briefly explain your answer for each fd (whythe fd is satisfied (or not)
by this relation value).
2.
Let R(ABC) be a relation with attributes A, B and C. Let
F
1
and
F
2
be sets of functional dependen
cies where
F
1
={ A
→
B, A
→
C}and
F
2
={A
→
B, B
→
C}.
(Here to get some intuitions about the relation R, you may think of R as representing information
about a person  attribute A represents the SSN of the person, attribute B represents the address of the
person, and attribute C represents the phone number of the person. However, this visualization of R
should NOTimpact your answers to the question)
(a)
This is the end of the preview. Sign up
to
access the rest of the document.
This note was uploaded on 01/25/2010 for the course CSC 4402 taught by Professor Staff during the Fall '08 term at LSU.
 Fall '08
 Staff
 Databases

Click to edit the document details