1. Dept. of Computer & Information Sciences
Riyadh Philanthropic Society For Science
Prince Sultan College For Woman
Dept. of Computer & Information Sciences
CS 340
Introduction to Database Systems
(Chapter 6 Tutorial)

2. Exercise 1 Given the Following database schema:
Specify the following queries in:
Relation algebra
Tuple relational calculus
Domain relational calculus
Only for a, b, c, f, i, j
Chapter 6 Tutorial 1

3. Exercise 1 - a
Retrieve the names of all employees in department 5 who work more than 10 hours per week on the ‘Product x’ project.
Relational Algebra:
PROJ_X  PNAME = ‘Product x’ (PROJECT)
EMP_WORK_  HOURS>10 (PROJ_X PNUMBER=PNO WORKS_ON)
EMP_DEPT_  DNO=5 (EMPLOYEE SSN=ESSN EMP_WORK_10)
RESULT p FNAME, LNAME (EMP_DEPT_5)
Chapter 6 Tutorial 2

4. Exercise 1 - a Tuple relational calculus:
{e.FNAME, e.LNAME | EMPLOYEE(e) AND e.DNO=5 AND
(p) (w) (PROJECT(p) AND WORKS_ON(w) AND p.PNAME=‘Product x’ AND w.HOURS>10 AND e.SSN=w.ESSN AND p.PNUMBER= w.PNO)}
Domain relational calculus:
{qs | (z) (a) (b) (e) (f) (g) (EMPLOYEE(qrstuvwxyz) AND PROJECT(abcd) AND WORKS_ON(efg) AND z=5 AND
a=‘Product x’ AND g>10 AND t=e AND b=f)}
Chapter 6 Tutorial 3

5. Exercise 1 - b
List the names of all employees who have a dependent with the same first name as themselves.
Relational Algebra:
EMP (EMPLOYEE SSN=ESSN AND FNAME=DEPENDENT_NAME DEPENDENT)
RESULT p FNAME, LNAME (EMP)
Chapter 6 Tutorial 4

6. Exercise 1 - b Tuple relational calculus:
{e.FNAME, e.LNAME | EMPLOYEE(e) AND (d) (DEPENDENT(d) AND e.SSN=d.ESSN AND
e.FNAME=d.DEPENDENT_NAME)}
Domain relational calculus:
{qs | (t) (a) (b) (EMPLOYEE(qrstuvwxyz) AND DEPENDENT(abcde) AND t=a AND q=b)}
Chapter 6 Tutorial 5

7. Exercise 1 - c
Find the names of all employees who are directly supervised by ‘Franklin Wong’.
Relational Algebra:
Domain relational calculus:
Tuple relational calculus:
Chapter 6 Tutorial 6

8. Exercise 1 - d
For each project, list the project name and the total hours per week (by all employees) spent on that project.
Relational Algebra:
Chapter 6 Tutorial 8

9. Exercise 1 - e
Retrieve the names of all employees who work on every project.
Relational Algebra:
Chapter 6 Tutorial 9

10. Exercise 1 - f
Retrieve the names of all employees who do not work on any project.
Relational Algebra:
Domain relational calculus:
Tuple relational calculus:
Chapter 6 Tutorial 10

11. Exercise 1 - g
For each department, retrieve the department name and the average salary of all employees working in that department.
Relational Algebra:
Chapter 6 Tutorial 12

12. Exercise 1 - h Retrieve the average salary of all female employees.
Relational Algebra:
Chapter 6 Tutorial 13

13. Exercise 1 - i
Find the names and addresses of all employees who work on at least one project located in Houston but whose department has no location in Houston.
Relational Algebra:
Domain relational calculus:
Tuple relational calculus:
Chapter 6 Tutorial 14

14. Exercise 1 - j
List the last names of all department managers who have no dependents.
Relational Algebra:
Domain relational calculus:
Tuple relational calculus:
Chapter 6 Tutorial 16