University of Delhi 2010-2nd Sem M.C.A 1st yr database system and implementation UNIVERSITY - Question Paper
[This question paper contains 3 printed pages ]
6260-A Your Roil No
M.Sc. COMPUTER SCIENCE/II Sem. J
MCS 203 - DATABASE SYSTEMS AND IMPLEMENTATION
(OC)
Time 2 hours Maximum Marks 40
(Write your Roll No on ike top immediately on receipt of this question paper)
Attempt all questions Use of calculator is allowed Parts of a question should be answered together
1 (a) What are the advantages of RAID level 5 over RAID level 4 9 Explain with the help of an example (3)
(b) Consider a disk with block size 512 bytes A block pointer is 6 bytes long, and a record pointer is 7 bytes long A file has 30,000 EMPLOYEE fixed length records of 115 bytes each SSN is one of the fields in a record and occupies 9 bytes Suppose the file is ordered by the key field SSN and we want to construct a primary index on SSN Calculate
(11) the number of first-level index entries and the number of first-level index blocks Assume that there is one index record for every block
m the data file
(2)
(hi) the number of levels needed if we make it
into a multi-level index
(2)
(c) Consider a disk with the following characteristics block size B = 512 bytes, interblock gap size = 128 bytes, number of blocks per track = 20, number of tracks per surface = 400 A disk pack consists of 15 double-sided disks What is the total capacity of a cylinder and what is its useful capacity (excluding interblock gaps) (2)
(a) What is a collision in flashing 7 Explain any two methods of collision resolution (3)
(b) Differentiate between the following
(t) clustering and non-clustering indexes
(u) nested and block nested loop join (5)
(c) What is an equivalence rule *> Where is it
3 (a) Consider the following relational schema
Employee (personName, street, city) Works(personName, companyName, salary) Company(companyName, location)
Given the following relational algebra expression II (CT
bmplmcc personName Woi ks company Name location location -
uiy \iarv 100000 (Employee {Xj Works [Xj Company)
Construct a relational algebra tree and a relational algebra expression that reflects the order of operations a query optimizer would choose for the given expression (5)
(b) What is a transaction 9 With the help of a diagiam, explain the \anous states a transaction goes through (5)
4 (a) What do you undeistand by serializabihiy n Briefly
explain various types of serial tzabilit> (5)
(b) What are locking protocols *> How is strict two-phase locking protocol different from rigorous two-phase locking protocol 7 (5)
(100)****
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