2007 Exam Paper

UNIVERSITY OF ABERDEEN SESSION 2006-2007
Examination in CS5035 (Introduction to Database Systems)
16 January 2007 (15:00 – 17:00 Hrs)
Answer any Three questions.
Use a separate answer book for each question.
Each question is worth 25 marks; the marks for each part of a question are shown in brackets.
1. (a) ‘Spreadsheet software (such as Microsoft Excel) offers a simple solution for storing data’. Critically evaluate the
above statement in comparison to storing data using a DBMS (such as Microsoft Access)? (3)
(b) Describe what you understand by the term ‘Relational Model’ and identify the main components of a relational
model. (5)
(c) In the context of relational databases, explain the term ‘referential integrity’. (2)
(d) Transform the following EER model fragment representing the relationship between MusicConcert and Artists
into a set of relations, explaining in detail the steps you have followed. (5)
MusicConcert
CID
CTitle
1..1 1..*
Artists
AID
lName
fName
(e) Transform the following EER model fragment representing the relationship between Movie and Cinema into a set
of relations, explaining in detail the steps you have followed. (5)
Movie
MID
MTitle
1..* 1..*
Cinema
CID
Address
(f) What is meant by third normal form (3NF)? Examine the following table to check if it is in 3NF. If yes, explain
your answer. Otherwise convert the table into 3NF. (Assume CarRegistrationNo as Primary Key) (5)
CarRegistrationNo DriverLicenceNo HireDate ReturnDate CarMake DriverName
TSG9720 EJ007823KS8 12/10/06 14/10/06 Mercedes Elton John
MGH9812 AW002364IG1 08/08/06 01/11/06 Ferrari Andrew Webber
ASB1001 BB009362UW6 22/01/06 12/12/06 BMW Boris Becker
SDK9812 IT001234AB5 15/06/06 31/12/06 Volvo Ian Thorpe

CS5035 (Introduction to Database Systems) - 2 - 2006-2007
The following questions (2, 3 & 4) refer to the relational tables listed below. These tables describe data related to a Project
Management System.
Assignments
TaskID StaffID StartDate EndDate
AM00090 cs01jf 15/09/2006 10/11/2006
AM00090 cs01rw 15/09/2006 15/10/2006
AM00090 cs03mp 16/10/2006 10/11/2006
CA00067 cs00aj 01/11/2006 05/11/2006
FT00017 cs00aj 01/08/2006 30/09/2006
FT00017 cs00gp 01/08/2006 01/09/2006
FT00017 cs03mp 01/09/2006 30/09/2006
Projects
ProjID ProjName ProjStartDate ProjEndDate ProjValue ProjBalance
RGA0896 FastTrack 12/05/2003 11/05/2008 £234,000.00 £87,000.00
RGB2091 CASE 01/01/2001 31/12/2010 £609,875.00 £28,900.00
RGD0941 DiveTalk 01/04/2005 31/03/2007 £79,000.00 £27,000.00
RGI6123 AuralMaps 01/09/2006 31/08/2009 £328,567.00 £298,123.00
Staff
StaffID fName lName YearsOfJavaExperience YearsOfSwingExperience YearsOfMySqlExperience
cs00aj Alice Johnson 8 8 5
cs00gp Gerald Pratt 12 12 5
cs01jf James Farmer 6 4 7
cs01rw Ralph Washington 3 3 1
cs03mp Mike Phillips 5 3 3
Tasks
TaskID TaskName Description Deliverable EstimatedTime ProjID
AM00090 Clusterer
Implementation
CA00067 Client Interview
Implement region growing
clusterer
Interview client from HAL,
Glasgow
clusterer java
class
Interview
Transcript
60 RGI6123
2 RGB2091
DT00145 Data backup Take backup of p3/data folder backup tape 1 RGD0941
FT00011 Corpus backup Take backup of p9/corpus folder backup tape 1 RGA0896
FT00017 Filter Implementation Implement segmentation filter filter java class 40 RGA0896

CS5035 (Introduction to Database Systems) 2006-2007
2. (a) In SQL, give one example of each of the following types of statements (use the Staff table if you need to refer to a
table in your answer)
(i) a Data Manipulation Language (DML) statement (1)
(ii) a Data Definition Language (DDL) statement (1)
(iii) a Data Control Language (DCL) statement (1)
(b) Write an SQL statement to add a new task to the database with the following details (use only the data specified below;
do not assume any new data):
TaskID: CA00033
TaskName: Code backup
Description: Take backup of p1/src folder
Deliverable: backup tape
ProjID: RGB2091 (2)
(c) Using only the Tasks table, write an SQL query to show the ‘sum’ of the estimated times which are larger than 10 hours
for all the tasks belonging to each of the projects. (5)
(d) Write an SQL query to show all the task names and their corresponding project names and sort the list in the ascending
order of project name and task name. (5)
(e) Write an SQL query to show all the task names and their corresponding project names assigned to Mike Phillips.
(5)
(f) Write an SQL query to show the first name and last names of those staff that have less than 2 tasks assigned. (5)

CS5035 (Introduction to Database Systems) - 4 - 2006-2007
3. (a) In relational database query processing, briefly explain the role played by relational algebra expressions and explain
how relational algebra trees (RATs) are used in query optimisation. (5)
(b) In a multi-user DBMS, user interactions with the DBMS server should fulfil four fundamental requirements denoted by
“ACID”. What does “ACID” stand for, and briefly describe the four requirements it represents? (4)
(c) What are views? Give one example each of a horizontal and a vertical view. (3)
(d) Explain how views and privileges help you to achieve fine grain access control over data in database tables. (4)
(e) Consider the following SQL query which refers to the Staff and Assignments tables given above:
SELECT *
FROM Staff S, Assignments A
WHERE S.StaffID = A.StaffID
AND S.lName='Washington'
AND S.fName='Ralph';
Using the relational algebra notation, σ P for selection with predicate P, × for a Cartesian product, for a natural join,
and for conjunction, write down three different but logically equivalent ways of expressing the above query in
relational algebra. In your answers, use the given table aliases for brevity, use brackets as necessary to avoid
ambiguities, and label your answers A, B and C. (6)
(f) In the database given above, suppose the Staff and Assignments tables have very many rows but have no indexes.
Arrange your solutions (A, B, C) from (e) in order of efficiency and justify your answer. (3)

CS5035 (Introduction to Database Systems) - 5 - 2006-2007
4. (a) MySQL mainly supports two table types called MYISAM and INNODB. Describe three ways in which these two table
types differ. (3)
(b) In a multi-user DBMS, sometimes deadlocks can occur between transactions. Describe in general terms when a
deadlock might occur and explain how deadlocks are usually detected and resolved in order to leave the database in a
consistent state. (5)
(c) With the help of a sketch, explain the various stages in which a request for a php file that contains MySQL queries is
processed by a web server. (3)
(d) Explain why symmetric key encryption is not a suitable method for encrypting data to be sent over the internet, and
briefly describe how the public key / private key technique largely addresses this problem. (5)
(e) What are the different types of spatial queries that spatial databases support? Describe one index scheme you will use to
enhance the performance of spatial queries. (4)
(f) List three different ways of file organization or access methods used in DBMSs. Discuss the performance of search,
insert and delete operations on each of the file organizations. (5)