Eastern Mediterranean University
Department of Computer
Engineering
143
CMPE 354 – Database Management Systems
Final Exam
2013 – 2014 Fall Semester
January 24, 2014
Name-Surname
:…………………..
Student No
:…………………..
Group
:…………………..
Instructor:
Assoc. Prof. Dr. Alexander CHEFRANOV
TIME: 150 MINUTES.
MOBILES ARE NOT ALLOWED!!!
THERE ARE TEN QUESTIONS. EACH QUESTION IS 10 POINT.
PLEASE ANSWER ALL QUESTIONS.
YOU CAN BRING IN ONE A4 SIZED SHEET OF HAND-WRITTEN NOTES TO THE EXAM.
PHOTOCOPIES ARE NOT ALLOWED !!!
Consider the following database
Employee(empno, name, office, age)
Books(isbn, title, authors, publisher)
Loan(empno, isbn, date)
Primary keys are underlined, foreign keys are used. The database will be used in the questions
below
1. (10 points) Build Entity-Relationship diagram for the database. Specify mapping
cardinality constraints, participation constraints. Explain how the constraints are
reflected in the ER diagram. Discuss the attributes (atomic, multi-valued, composite,
derived). Change, if necessary, some attributes; give reasons for that.
Employee
books
loan
empno
isbn
date
title
name
publisher
office
birthday
y
authors
age
Relation loan is binary many-to-many, with partial participation of books and
Employee. Authors is a multivalued attribute, age is a derived from birthday attribute
2
2. (10 points) Represent the database by the tabular schema diagram where each table is
represented by a box with attributes inside it, primary keys are underlined, and foreign
keys are shown by arrows directed from a referencing table to the referenced one.
Hint: Some attributes may need a separate table
Employee
Loan
books
Empno
Empno
isbn
name
isbn
title
office
publisher
Authors
author
isbn
birthday
3
3. (10 points) Write a relational algebra expression for the following query: Find names
of employees who borrowed more than three books published by Addison Wesley.
 name (employee   c _ tit3 (  X ( empno,c _ tit) ( empno Gcount(title) (loan   publisher ' AW ' (books)))))
4. (10 points) Write a relational algebra expression for the following query: Find titles of
the books with more than two authors. Hint: You may need a separate table for authors
attribute in the database
 title (books   c _ auth 2 ( isbn Gcount( author) as
c _ auth
(authors)))
4
5. (10 points) Write an SQL expression for the following query: Find names of
employees who borrowed more than three books published by Addison Wesley.
Select name
From employee
Where empno in (
Select empno
From loan
Where isbn in (select isbn from books where publisher=’AW’)
Group by empno
Having count(*)>3
)
6. (10 points) Write an SQL expression for the following query: Find titles of books with
more than two authors. Hint: You may need a separate table for authors attribute in the
database
Select title
From books
Where isbn in (
Select isbn
From authors
Group by isbn
Having count(*)>2
)
5
7. (10 points) Consider the C code below:
Char*sqlprog=”update account set balance=balance*1.05 where account.number=?”;
Sqlprog is an array containing SQL query of increasing balance of an account
specified as a parameter of that query
EXEC SQL prepare dynprog from :sqlprog;
SQL query is prepared for launching as dynprog from the program variable sqlprog
Char account[10]=”A-101”;
account is a 10-element array initialized by “A-101”
EXEC SQL execute dynprog using :account;
SQL query from dynprog is invoked with parameter from the program variable
account
Explain the meaning of the code as a whole and each its line in particular.
The code as a whole invokes an SQL query increasing by 5% balance of account A-101.
6
8. (10 points) Write a function in SQL with one input: Publisher. The function returns
names of employees who borrowed more than three books published by the Publisher
Hint: Consider the code below:
Create function accounts_of(customer_name char(20))
Returns table(account_number char(10),
Branch_name char(15),
Balance numeric(12,2))
Return table(
Select account_number, branch_name, balance
From account
Where exists(
Select *
From depositor
Where depositor.customer_name=accounts_of.customer.name
And
depositor.account_number=account.account_number)
)
Adjust the code above to solve your problem
Create function emp_names(Publisher char(20))
Returns table(name char(10)
)
Return table(
Select name
From employee
Where empno in (
Select empno
From loan
Where isbn in (
select isbn from books b
where b.publisher=emp_names.Publisher
)
Group by empno
Having count(*)>3
)
)
7
9. (10 points)
Consider the code below
Create trigger reorder_trigger after update of amount on inventory
Reorder_trigger is defined that is invoked after update of amount attribute of inventory
relation
Referencing old row as orow, new row as nrow
Orow contains modified tuple value before update, nrow contains modified tuple value
after update
For each row
For each modified tuple to be done
When nrow.level<=(select level from minlevel where minlevel.item=orow.item)
If level of the item after update is less or equal to the value shown for that item in
minlevel table
And orow.level>(select level from minlevel where minlevel.item=orow.item)
And if before update level of the item was greater than the value shown for that item
in the minlevel table
then
Begin
Insert into orders
Into orders relation
(select item, amount
Item and amount are inserted
From reorder
Taken from reorder table
Where reorder.item=orow.item)
Where item value matches to that used in the modified tuple referred to by orow
end
Explain functionality of the code as a whole and each its line in particular.
The trigger is invoked after update of amount attribute of inventory relation. It checks
whether the current level of an item falls below the specified minimal value, and if so,
it inserts into orders relation amount of the item necessary to purchase taken from the
reorder relation.
8
10. (10 points) Write an SQL expression to give the users Bob and Alice privileges on
update authors in books and insertion into loan.
Grant update(authors) on books, insert on loan to Bob, Alice
9