IT-240 Self-Test

This is on-line Assessment Examination. Once you complete and submit the test, the test will be graded and you will be notified of the results. Please work with your advisor after notification to discuss course selection and other program issues.


  1. A relationship between two sets A and B is:
    
    A subset of A - B
    A subset of A Ç B
    A subset of A È B
    A subset of A x B
    None of the above
  2. A sound reason to why storing data in a database can be superior to storing it in files is:
    
    A database provides much larger storage space than a file does
    A database system provides concurrency control whereas a file system does not
    A database can be accessed through the internet whereas a file system cannot
    None of the above
  3. The fact that in a database system changing the data types does not necessarily lead
    to changing the data access methods, is referred to as:
    
    Data consistency
    Minimal data redundancy
    Data security
    Program-data independence
    None of the above
  4. A multivalued attribute of an entity class is:
    
    An attribute with several components that need to be put together to determine the value of the attribute
    An attribute whose value is not stored but rather computed from multiple existing attribute values
    An attribute whose value is a collection of values
    An attribute that uniquely determines all other attributes of the entity class
    None of the above
  5. A derived attribute is usually represented in the E-R diagram by:
    
    Drawing it underlined inside an oval
    Drawing it inside a rectangle
    Drawing it inside a double oval
    Drawing it inside a dashed oval
    None of the above
  6. A many-to-many relationship type R between two entity classes S and T is represented in relational model by:
    
    Adding the key attribute of S to the schema of T
    Adding the key attribute of T to the schema of S
    Creating a new schema for the relationship type R
    None of the above

  7. 
    
    In the above E-R diagram, the attribute Ename of the entity class Employee is:
    
    A composite attribute
    A multivalued attribute
    A derived attribute
    A key attribute
    None of the above
  8. Which of the following statements best describes the attribute Color in the above E-R diagram?
    
    Automobiles cannot be of multiple colors and any given automobile cannot have multiple colors simultaneously
    Automobiles cannot be of multiple colors but any given automobile can have multiple colors simultaneously
    Automobiles can be of multiple colors and any given automobile can have multiple colors simultaneously
    Automobiles can be of multiple colors but any given automobile cannot have multiple colors simultaneously
    None of the above
  9. Based on the above E-R diagram, which of the following statements is TRUE?
    
    Every employee is assigned an automobile
    Every automobile is assigned to an employee
    Every employee has a reference
    A reference may or may not belong to an employee
    None of the above
  10. Which of the following relations is part of your relational schema when mapping 
    the above E-R diagram to a relational schema?
    
    Reference(Emp#, RName, Title, NumberOf)
    Employee(Emp#, First, Last, VIN#, Date)
    Automobile(VIN#, Emp#, Color, Date)
    Color(VIN#, Color)
    None of the above
  11. Based on the above given E-R diagram, RName is a(n)
    
    Candidate key
    Partial key
    Foreign key
    Primary key
    None of the above
  12. Which of the following is the complete mapping of the above E-R diagram to a relational schema?
    

    Reference(Emp#, RName, Title, NumberOf)
    Employee(Emp#, EName, First, Last, VIN#, Date)
    Automobile(VIN#, Emp#, Color, Date)
    Color(VIN#, Color)


    Reference(Emp#, RName, Title)
    Employee(Emp#, EName, First, Last, VIN#, Date)
    Automobile(VIN#, Emp#, Date)
    Color(VIN#, Color)


    Reference(Emp#, RName, Title)
    Employee(Emp#, EName, First, Last, VIN#, Date)
    Automobile(VIN#)
    Color(VIN#, Color)


    Reference(Emp#, RName, Title)
    Employee(Emp#, EName, VIN#, First, Last)
    Automobile(VIN#, Emp#, Date)
    Color(VIN#, Color)

    None of the above
  13. Consider the following relational schema
    
    Employee (SSN, Fname, Lname,Superssn, Dept_Num)
    Department (Dept_Number, Dept_Name)
    Dependent (Emp_SSN, Dependent_Name)
    Project (Project_Number, Project_Name, Dept_Num)
    Works_On (Emp_SSN, Proj_Num). 
    
    Which of the following SQL statements retrieves all the employees with no dependents?
    
    
    Select * from Employee, Dependent where Dependent_Name = NULL;
    Select * from Employee, Dependent where (SSN=Emp_SSN) and (Dependent_Name = NULL)
    Select * from Employee where not Exists(Select * from Dependent where SSN = Emp_SSN);
    Select * from Employee where SSN IN (select Emp_SSN from Dependent where Emp_SSN = NULL);
    None of the above
  14. Based on the above relational schema, which SQL statement lists, for every project, the project number, 
    and the number of employees working on the project?
    
    Select Pnumber, count(*) from Employee, Project where Employee.Dept_Num = Project.Dept_Num;
    Select Proj_Num, count(*) from Works_On group by Proj_Num;
    Select Proj_Num, count(*) from Works_On, Employee where SSN = Emp_SNN;
    Select Proj_Num, count(*) from Employee, Project;
    None of the above
  15. Based on the above relational schema, which SQL statement lists the name of every 
    employee whose supervisor's first name is Pinocchio, or the first name of his 
    supervisor's supervisor is Pinocchio?
    
    Select Fname, Lname from Employee where Fname='Pinocchio';
    Select Fname, Lname from Employee E1, Employee E2 where (E1.SSN = E2.SSN) and (Fname = 'Pinocchio');
    Select Fname, Lname from Employee E1, Employee E2, Employee E3 where ((E1.Superssn = E2.SSN) and (E2.Fname = 'Pinocchio')) or ((E1.Superssn = E2.SSN) and (E2.Superssn = E3.SSN) and (E3.Fname = 'Pinocchio'));
    Select Fname, Lname from Employee E1, Employee E2 where ((E1.Superssn = E2.SSN) and (E2.Fname = 'Pinocchio'))
    None of the above