Choose a set of transactions for an application of your choice (other than a banking or student registration system). For each isolation level weaker than SERIALIZABLE, give an example of a schedule that produces an erroneous situation.
What will be an ideal response?
Airline reservation system:
REPEATABLE READ
(SELECT and print list : passengers on flight 100)1
(Make newreservation on flight 100)2
(Read and print item : number of passengers on flight 100)1
Printout is inconsistent
READ COMMITTED
(read : seat 5B is empty)1
(read : seat 5B is empty)2 (reserve seat 5B for passenger 10)2 commit2
((reserve seat 5B for passenger 127)1
Seat 5B is reserved for two passengers.
READ UNCOMMITTED
(write request item : passenger requests exotic meal for seat 5B)1
(read request item; write order item : order meal from caterer )2 commit2
abort1
Meal has been ordered that passenger does not want.
Computer Science & Information Technology
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A footnote is a reference that is placed at the end of a document or chapter
Indicate whether the statement is true or false
Computer Science & Information Technology
A computer program that searches for Web pages, examines the content of pages, and reports the findings back to a central computer is called a ________
A) knowledge base B) Web crawler C) page ranker D) sponsored link
Computer Science & Information Technology
One form of spoofing involves forging the return address on an e-mail so that the e-mail message appears to come from someone other than the sender.
a. true b. false
Computer Science & Information Technology
Firewalls are not usually a combination of hardware and software.
a. true b. false
Computer Science & Information Technology