UNIVERSITY EXAMINATIONS: 2011/2012
YEAR III EXAMINATION FOR THE BACHELOR OF SCIENCE IN
INFORMATION TECHNOLOGY
BIT4306 DISTRIBUTED DATABASES
DATE: APRIL 2012 TIME: 2 HOURS
INSTRUCTIONS: Answer Question One and Any other Two Questions
Question One
a) Differentiate between the following terms:
i) Distributed processing vs Cooperative processing [4 Marks]
ii) Data Warehouse vs Distributed database [4 Marks]
iii)Distributed processing vs Database link [4 Marks]
b) Describe the major concepts used to facilitate connectivity between Oracle DBMS and a non
Oracle DBMS [6 Marks]
c) Explain how shared links differ from standard database links [6 Marks]
d) Examine the main factors you need to consider when setting up user accounts and roles [6 Marks]
Question Two
a) Elaborate on the following distributed query optimization methods
i) Collocated Inline Views [2 Marks]
ii) Using Cost-Based Optimization [2 Marks]
b) There are two types of permissible operations in distributed transactions: DML and DDL
Transactions as well as Transaction Control Statements. Outline any two operations supported by
each [4 Marks]
c) Describe how the global coordinator controls distributed transactions in a distributed database,
[6 Marks]
d) Outline the three ways in which Distributed transactions can become in-doubt [6 Marks]
Question Three
a) Explain the following Four strategies regarding placement of data
i) Centralized [2 Marks]
ii) Partitioned [2 Marks]
iii)Complete Replication [2 Marks]
iv)Selective Replication [2 Marks]
b) In your own opinion which architecture is suitable for distributed databases [4 Marks]
c) Using examples elaborate on the importance of Database Links in distributed databases?[2 Marks]
d) Using SQL show how Views can be used to create location transparency in a distributed database
[6 Marks]
Question Four
a) Outline any four applications that use distributed databases concepts [4 Marks]
b) What benefits are provided by views in databases? [6 Marks]
c) Query processing is a three step process that transforms a high-level query of relational calculus
into an equivalent and more efficient lower-level query of relational algebra. Describe the
activities involved in Query processing [6 Marks]
d) Explain the properties of a transaction [4 Marks]
Question Five
a) Briefly explain how the Two-Phase Commit Mechanism in distributed databases ensures data
integrity [5 Marks]
b) Do you think the following are distributed database management systems or not?
i) Distributed Processing [2 Marks]
ii) Parallel DBMS [2 Marks]
c) Using a relevant example explain the concept of a Remote Procedure Calls (RPCs) in distributed
databases [6 Marks]
d) Briefly explain how Distributed Query Optimization is achieved in oracle databases [5 Marks]
