CSCI 4380 Final Exam
Ian S. Steenstra
TOTAL POINTS
89 / 100
3 Question
QUESTION 1
1 Question
1( a) 7 / 8
✓ - 0 pts Correct
1 (c) 6 / 10
✓ - 0 pts Checked
- 0 pts Correct
- 1 pts very minor syntax or other errors
- 10 pts Missing/Incorrect
- 2 pts some syntax errors
- 1 pts Very minor syntax errors
- 1 pts incorrect aggregates in SELECT
- 2 pts Some syntax errors
- 2 pts incorrect/missing relations for FROM
✓ - 2 pts Does not account for zero members (no left
- 1 pts incorrect/missing join with bannedusers
join or equivalent)
- 1 pts incorrect/missing select on banned status
✓ - 1 pts incorrect/missing group by
- 1 pts incorrect/missing having condition
- 1 pts Missing/incorrect count in select
- 1 pts Missing/incorrect join between channel and
roles
- 1 pts missing nickname in SELECT
- 1 pts Missing member roletype selection
- 1 pts missing count in SELECT
- 1 pts Missing selection on channel creation date
- 1 pts missing users in FROM
- 1 pts Missing group by
- 8 pts missing/incorrect
- 3 pts Incorrect selection for channels with fewest
members
✓ - 2 pts Missing/incorrect subquery for channels
QUESTION 2
2 Question
1 (b) 4 / 8
- 0 pts Correct
- 1 pts very minor syntax errors or missing DISTINCT
✓ - 2 pts some syntax errors
✓ - 1 pts incorrect/missing method to find pairs of
with fewest members
- 1 pts Missing/incorrect order by
QUESTION 4
4 Question
1 (d) 12 / 12
different users
✓ - 0 pts Checked
✓ - 1 pts does not correctly exclude one of A,B or B,A
✓ - 0 pts Correct
- 1 pts does not guarantee returned users subscribe
to one channel
- 12 pts Missing/Incorrect
- 1 pts Very minor syntax errors
- 2 pts incorrect: finding users who share a channel
- 2 pts Some syntax errors
- 3 pts incorrect: excluding users who share a
- 1 pts Missing/incorrect count for messages in
channel
-- no not exists, except or equivalent
select
- 1 pts Missing/incorrect count for channels in select
- 1.5 pts set subtraction is not set compatible
- 1 pts Missing/incorrect username in select
- 8 pts incorrect/missing
- 2 pts Missing/incorrect check for invite permission
- 2 pts NOT EXISTS statement errors
- 2 pts Missing/incorrect check for ban permission
- 1 pts Missing/incorrect join between different
QUESTION 3
permissions
- 1 pts Missing/incorrect join with messages on
username
250*1/5000)
- 1 pts Missing/incorrect group by
- 1 pts Missing/incorrect having
- 1 pts Missing/incorrect having condition
- 1 pts incorrect i2 relation read cost (40 or
200,000/5,000)
- 2 pts incorrect I3 index leaf scan cost (1000)
- 1 pts incorrect I3 relation cost (0)
QUESTION 5
5 Question
- 1 pts incorrect I1 internal level scan cost (2)
2 5/6
- 0 pts Correct
- 1 pts (a) incorrect answer
✓ - 1 pts (a) incorrect explanation (should explicitly
- 1 pts incorrect I2 internal level cost (2)
✓ - 1 pts incorrect I3 internal level scan cost (2)
- 12 pts completely incorrect/missing
- 9 pts mostly wrong
mention any message that references it in the
replyto mid field is also deleted).
- 1 pts (b) incorrect answer
- 2 pts (b) does not mention failure for bannedusers
- 1 pts (b) does not mention cascades to roles and
messages explicityly
- 1 pts (b) missing some cascades
- 4 pts (b) missing/incorrect answer
- 1 pts mention failure for bannedusers but adding a
question mark
QUESTION 8
8 Question
4 8/8
✓ - 0 pts Correct
- 1 pts (a) incorrect key
- 1 pts (a) incorrect BCNF conclusion given the key
- 1 pts (a) incorrect/missing explanation of BCNF
conclusion
- 1 pts (a) missing/incorrect problem with the relation
- 1 pts (b) incorrect key
- 1 pts (b) incorrect BCNF conclusion given the key
QUESTION 6
6 Question
- 1 pts (b) missing explanation of BCNF conclusion
3 (a-b) 8 / 8
✓ - 0 pts Correct
- 1 pts (a) missing/incorrect explanations
- 1 pts (b) missing/incorrect problem with the
relation
- 8 pts missing/incorrect
- 1 pts (b) missing/incorrect explanations
- 1 pts (a) missing/incorrect step 1 cost
QUESTION 9
- 2 pts (a) missing/incorrect step 2 cost
9 Question
- 1 pts (a) partially incorrect step 2 cost
5 5/5
✓ - 0 pts Correct
- 1 pts (b) missing/incorrect cost for relation R
- 1 pts incorrect/missing keys
- 2 pts (b) missing/incorrect cost for relations S
- 1 pts missing ABCE
- 1 pts (b) partially incorrect cost for relation S
- 1 pts missing EFGHI
- 8 pts missing/completely incorrect
- 1 pts missing ACF
- 1 pts missing ABDF or CBDF
QUESTION 7
7 Question
- 1 pts incorrect decomposition
3 (c) 11 / 12
- 0 pts Correct
- 2 pts incorrect I1 index leaf scan cost (50 or
- 1 pts missing functional dependencies for
decomposed relations
- 5 pts missing/incorrect
500*11/100)
- 1 pts incorrect I1 relation read cost (4 or
200,000*11/100*1/5000)
- 2 pts incorrect I2 index leaf scan cost (1-2 or
QUESTION 10
10 Question
6 9/9
✓ - 0 pts Correct
- 0.5 pts missing dateAdded relationship attribute
- 1 pts missing by relationship
- 9 pts missing/incorrect
- 0.5 pts (a) incorrect response
- 0.5 pts (a) incorrect/missing explanation
- 0.5 pts (b) incorrect response
- 0.5 pts (b) incorrect/missing explanation
- 0.5 pts (c) incorrect response
- 0.5 pts (c) incorrect/missing explanation
- 1 pts missing comment entity
- 0.5 pts missing/incorrect key for comment entity
- 1 pts missing areFor relationship
- 1 pts missing prefers relationship
- 1 pts some missing/incorrect participation
constraints
- 2 pts many missing/incorrect participation
constraints
- 1 pts missing new relationship names
QUESTION 11
11 Question
7 10 / 10
✓ - 0 pts Checked
✓ - 0 pts Correct
- 1 pts incorrect/missing conclusion based on
conflict graph
- 2 pts missing r2(x)-w1(x) conflict
- 2 pts missing r1(z)-w3(z) conflict
- 2 pts missing w2(w)-r3(w) conflict
- 2 pts one incorrect conflict
- 4 pts two or more incorrect conflicts
- 1 pts incorrect/missing conflict graph
- 2 pts incorrect/missing equivalent serial schedule
QUESTION 12
12 Question
8 4/4
✓ - 0 pts Checked
✓ - 0 pts correct
- 4 pts missing/incorrect
- 1 pts (a) incorrect steal conclusion
- 1 pts (a) incorrect steal explanation
- 1 pts (b) incorrect force conclusion
- 1 pts (b) incorrect force explanation
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