Question 1

CLASS Employee {
//Variables
String LastName;
String FirstName;
Real HourlyRate;
Integer HoursWorked;
String Job;
Date HireDate;
Real Monthly_Salary;
//Methods
String GetLastName();
String GetFirstName();
String GetJob();
Real GetSalary();}
The class Clerk is a subclass of the class Employee
CLASS Clerk: Employee {
//Variables
Real HourlyRate;
Integer HoursWorked;
//Methods
Real GetSalary();}
The class Salesperson is a subclass of the class Employee
CLASS Salesperson: Employee {
//Variables
Real Base_Salary;
Real Commission_rate
Real Sales;
//Methods
Real GetSalary();}
The class PartClerk is a subclass of the classes Clerk and Salesperson
CLASS PartClerk: Clerk, Salesperson {
//Variables
Real PercentClerk;
//Methods
Real GetPercentClerk();}

-If there is an object for a clerk with last name Lopez,the following method will be used to compute Lopez's salary:

Accepted Answer

Since Lopez is a clerk, it is most appropriate to use the GetSalary method defined in the Clerk class. Using the one defined in the Employee class may not take into account any specific attributes or calculations for clerks. A new method created only for the Lopez object is not a good practice as it can lead to code duplication and maintenance issues. There is no ambiguity as the object is clearly identified as a clerk.

Question 2

Which of the following applications is supported by a relational DBMS?

Accepted Answer

A relational DBMS is a database management system that uses relational techniques for storing and retrieving data. It is best suited for applications that require storing and retrieving structured data, such as a list of suppliers for a spare part identified by its code number. Options A and C are better suited for applications that require either a graphical user interface or multimedia support.

Question 3

CLASS Employee {
//Variables
String LastName;
String FirstName;
Real HourlyRate;
Integer HoursWorked;
String Job;
Date HireDate;
Real Monthly_Salary;
//Methods
String GetLastName();
String GetFirstName();
String GetJob();
Real GetSalary();}
The class Clerk is a subclass of the class Employee
CLASS Clerk: Employee {
//Variables
Real HourlyRate;
Integer HoursWorked;
//Methods
Real GetSalary();}
The class Salesperson is a subclass of the class Employee
CLASS Salesperson: Employee {
//Variables
Real Base_Salary;
Real Commission_rate
Real Sales;
//Methods
Real GetSalary();}
The class PartClerk is a subclass of the classes Clerk and Salesperson
CLASS PartClerk: Clerk, Salesperson {
//Variables
Real PercentClerk;
//Methods
Real GetPercentClerk();}

-If there are two clerks with identical data (same last name,first name,...):

Accepted Answer

To differentiate between the two clerks, the program needs to create two separate objects. Adding a unique system-generated identifier ensures that each object is unique and can be accessed independently.

Question 4

CLASS Employee {
//Variables
String LastName;
String FirstName;
Real HourlyRate;
Integer HoursWorked;
String Job;
Date HireDate;
Real Monthly_Salary;
//Methods
String GetLastName();
String GetFirstName();
String GetJob();
Real GetSalary();}
The class Clerk is a subclass of the class Employee
CLASS Clerk: Employee {
//Variables
Real HourlyRate;
Integer HoursWorked;
//Methods
Real GetSalary();}
The class Salesperson is a subclass of the class Employee
CLASS Salesperson: Employee {
//Variables
Real Base_Salary;
Real Commission_rate
Real Sales;
//Methods
Real GetSalary();}
The class PartClerk is a subclass of the classes Clerk and Salesperson
CLASS PartClerk: Clerk, Salesperson {
//Variables
Real PercentClerk;
//Methods
Real GetPercentClerk();}

-The class Clerk does not inherit the following data from the class Employee:

Accepted Answer

Clerk class does inherit the variable HourlyRate from the Employee class, but it is redeclared in the Clerk class, indicating it is specifically defined for Clerk, not inherited as a unique or new variable. All other variables listed (LastName, Job, HireDate) are inherited from Employee and are not redefined in the Clerk class, making them inherited properties.

Question 5

SQL:1999 supports the definition of structured data types,which are used to bundle a collection of attributes and methods together.

Accepted Answer

SQL:1999 does support the definition of structured data types, which allow for the bundling of attributes and methods together.

Question 6

Since Oracle 9i differs from SQL:1999 in that system-generated object identifiers are not explicitly named,the REF function must be used in data manipulation statements in Oracle 9i to retrieve the object identifier.

Accepted Answer

Oracle 9i requires the REF function to retrieve object identifiers since they are not explicitly named. This is different from SQL:1999 where object identifiers are explicitly named.

Question 7

CLASS Employee {
//Variables
String LastName;
String FirstName;
Real HourlyRate;
Integer HoursWorked;
String Job;
Date HireDate;
Real Monthly_Salary;
//Methods
String GetLastName();
String GetFirstName();
String GetJob();
Real GetSalary();}
The class Clerk is a subclass of the class Employee
CLASS Clerk: Employee {
//Variables
Real HourlyRate;
Integer HoursWorked;
//Methods
Real GetSalary();}
The class Salesperson is a subclass of the class Employee
CLASS Salesperson: Employee {
//Variables
Real Base_Salary;
Real Commission_rate
Real Sales;
//Methods
Real GetSalary();}
The class PartClerk is a subclass of the classes Clerk and Salesperson
CLASS PartClerk: Clerk, Salesperson {
//Variables
Real PercentClerk;
//Methods
Real GetPercentClerk();}

-The class Clerk does not inherit the following method from the class Employee:

Accepted Answer

Clerk class overrides the GetSalary method, meaning it provides its own implementation rather than inheriting it from the Employee class.

Question 8

CLASS Employee {
//Variables
String LastName;
String FirstName;
Real HourlyRate;
Integer HoursWorked;
Date HireDate;
String Job;
//Methods
Real Salary();
String GetLastName();
String GetFirstName();
String GetJob();}

-If the type of the data HoursWorked is changed from integer to real,the following will need to be changed:

Accepted Answer

Only the method Salary() needs to be changed because it will now need to calculate the salary using a decimal value for HoursWorked. The program that displays the Employee's name and salary will still work as expected because the change from integer to real will not affect the output of the salary calculation.

Question 9

Which of the following applications is supported by an object DBMS?

Accepted Answer

Object DBMSs are designed to handle complex data and relationships, such as multimedia objects, CAD objects, and more. All the given applications (A: using drawings to identify parts, B: listing suppliers based on part codes, C: showing disassembly instructions) involve managing and querying complex data and relationships that an object DBMS is well-suited to support.

Question 10

Oracle 9i follows the SQL:1999 standard in supporting row types,subtables and typed tables.

Accepted Answer

Oracle 9i does not fully support SQL:1999 standards such as row types, subtables, and typed tables. While it introduced some object-relational features, it did not fully implement all the SQL:1999 specifications for these elements.

Question 11

CLASS Employee {
//Variables
String LastName;
String FirstName;
Real HourlyRate;
Integer HoursWorked;
String Job;
Date HireDate;
Real Monthly_Salary;
//Methods
String GetLastName();
String GetFirstName();
String GetJob();
Real GetSalary();}
The class Clerk is a subclass of the class Employee
CLASS Clerk: Employee {
//Variables
Real HourlyRate;
Integer HoursWorked;
//Methods
Real GetSalary();}
The class Salesperson is a subclass of the class Employee
CLASS Salesperson: Employee {
//Variables
Real Base_Salary;
Real Commission_rate
Real Sales;
//Methods
Real GetSalary();}
The class PartClerk is a subclass of the classes Clerk and Salesperson
CLASS PartClerk: Clerk, Salesperson {
//Variables
Real PercentClerk;
//Methods
Real GetPercentClerk();}
 CLASS Employee {
//Variables
String LastName;
String FirstName;
Real HourlyRate;
Integer HoursWorked;
String Job;
Date HireDate;
Real Monthly_Salary;
//Methods
String GetLastName();
String GetFirstName();
String GetJob();
Real GetSalary();}
The class Clerk is a subclass of the class Employee
CLASS Clerk: Employee {
//Variables
Real HourlyRate;
Integer HoursWorked;
//Methods
Real GetSalary();}
The class Salesperson is a subclass of the class Employee
CLASS Salesperson: Employee {
//Variables
Real Base_Salary;
Real Commission_rate
Real Sales;
//Methods
Real GetSalary();}
The class PartClerk is a subclass of the classes Clerk and Salesperson
CLASS PartClerk: Clerk, Salesperson {
//Variables
Real PercentClerk;
//Methods
Real GetPercentClerk();}
 CLASS Employee {
//Variables
String LastName;
String FirstName;
Real HourlyRate;
Integer HoursWorked;
String Job;
Date HireDate;
Real Monthly_Salary;
//Methods
String GetLastName();
String GetFirstName();
String GetJob();
Real GetSalary();}
The class Clerk is a subclass of the class Employee
CLASS Clerk: Employee {
//Variables
Real HourlyRate;
Integer HoursWorked;
//Methods
Real GetSalary();}
The class Salesperson is a subclass of the class Employee
CLASS Salesperson: Employee {
//Variables
Real Base_Salary;
Real Commission_rate
Real Sales;
//Methods
Real GetSalary();}
The class PartClerk is a subclass of the classes Clerk and Salesperson
CLASS PartClerk: Clerk, Salesperson {
//Variables
Real PercentClerk;
//Methods
Real GetPercentClerk();}

-If there are two employees with last names respectively Smith and Martin,which of the following statements is not true?

Accepted Answer

The statement "Only one object of the class Employee may exist at a given time" is not true as multiple objects can be created from the same class to represent different employees. Therefore, option B is the correct answer.

Question 12

CLASS Employee {
//Variables
String LastName;
String FirstName;
Real HourlyRate;
Integer HoursWorked;
Date HireDate;
String Job;
//Methods
Real Salary();
String GetLastName();
String GetFirstName();
String GetJob();}

-The ability by a program do to the following violates encapsulation principles:

Accepted Answer

Directly accessing LastName violates encapsulation principles because it exposes the internal implementation details of the program and makes it more difficult to maintain and update the code in the future.

Answer: B and C 
 Retrieving LastName and Job with methods that have been specifically designed to return those values (i.e. GetLastName() and GetJob()) is a better approach to accessing those properties because it still maintains the encapsulation principles by hiding the internal implementation details of the program.

Answer: D 
 Computing salary with a method called Salary() is a valid use of encapsulation principles because it is providing a service for the user of the program and does not expose the internal implementation details of the program.

Question 13

SQL-1999 supports multiple inheritance of subtypes by allowing more than one type name to be listed after the UNDER keyword in the CREATE TYPE statement.

Accepted Answer

SQL:1999 does not support multiple inheritance for subtypes; it allows only single inheritance, meaning a subtype can inherit from only one supertype at a time.

Question 14

Oracle 9i,differs from SQL:1999 in that if two methods have the same name but different signatures (i.e.number,types,and order of parameters)there is no overriding of the methods in Oracle9i.

Accepted Answer

In Oracle 9i, methods with the same name but different signatures (differing in number, types, and order of parameters) are considered as overloaded methods, not overridden. Overriding pertains to methods in subclasses having the same signature as in the superclass, which is a concept more aligned with object-oriented programming languages rather than SQL standards or database method implementations.

Question 15

Only methods that have been explicitly defined in the CREATE TYPE statement of a user-defined type can be used in SQL statements and stored procedures.

Accepted Answer

SQL Server allows for the invocation of methods not only explicitly defined in the CREATE TYPE statement but also those inherited from a base type or added later through the ALTER TYPE statement, expanding the functionality of user-defined types beyond their initial definition.

Question 16

CLASS Employee {
//Variables
String LastName;
String FirstName;
Real HourlyRate;
Integer HoursWorked;
String Job;
Date HireDate;
Real Monthly_Salary;
//Methods
String GetLastName();
String GetFirstName();
String GetJob();
Real GetSalary();}
The class Clerk is a subclass of the class Employee
CLASS Clerk: Employee {
//Variables
Real HourlyRate;
Integer HoursWorked;
//Methods
Real GetSalary();}
The class Salesperson is a subclass of the class Employee
CLASS Salesperson: Employee {
//Variables
Real Base_Salary;
Real Commission_rate
Real Sales;
//Methods
Real GetSalary();}
The class PartClerk is a subclass of the classes Clerk and Salesperson
CLASS PartClerk: Clerk, Salesperson {
//Variables
Real PercentClerk;
//Methods
Real GetPercentClerk();}

-An object of the class PartClerk is created for Lee (last name).Given the information shown,the method GetSalary:

Accepted Answer

Given the information, it's not clear which version of the GetSalary method would be used for an object of the class PartClerk since it inherits from both Clerk and Salesperson, which each have their own GetSalary method. This ambiguity makes it impossible to determine without further details on how the inheritance is resolved or if there's an overriding method in PartClerk.

Question 17

In client-server processing:

Accepted Answer

A) In client-server processing, a client can be viewed as an object that requests services from a server. 
B) Objects can be distributed on different computers in a client-server model for better performance and scalability. 
C) The DBMS (database management system) ensures proper binding of a method, which means that it matches the method call made by the client to the corresponding method on the server. Thus, all of the given choices are correct.

Question 18

In SQL:1999,functions and procedures can overcome some of the limitations of SQL:1999 methods.

Accepted Answer

Functions and procedures in SQL:1999 can be used to perform more complex tasks and manipulate data in ways that plain SQL queries cannot achieve. They can also be used to perform calculations, validations, and other tasks on data before storing or retrieving it from a database. Therefore, they can help overcome some of the limitations of SQL:1999 methods.

Question 19

CLASS Employee {
//Variables
String LastName;
String FirstName;
Real HourlyRate;
Integer HoursWorked;
Date HireDate;
String Job;
//Methods
Real Salary();
String GetLastName();
String GetFirstName();
String GetJob();}

-Which of the following is not part of the interface?

Accepted Answer

The interface of a class consists of the methods that can be called by objects outside the class. "Date HireDate" is a variable, not a method, making it not part of the interface.

Question 20

Which of the following requires object database technology?

Accepted Answer

Storing and retrieving an employee picture can be done using traditional file-based systems or relational databases. Displaying an employee picture on a screen requires only basic programming techniques. However, if the employee picture needs to be processed along with other data (such as employee information), an object database is likely the best solution as it can store both the image and the related metadata in a unified and more efficient way.

Quiz 18: Object Database Management Systems

Which of the following applications is supported by a relational DBMS?

SQL:1999 supports the definition of structured data types,which are used to bundle a collection of attributes and methods together.

Since Oracle 9i differs from SQL:1999 in that system-generated object identifiers are not explicitly named,the REF function must be used in data manipulation statements in Oracle 9i to retrieve the object identifier.

Which of the following applications is supported by an object DBMS?

Oracle 9i follows the SQL:1999 standard in supporting row types,subtables and typed tables.

SQL-1999 supports multiple inheritance of subtypes by allowing more than one type name to be listed after the UNDER keyword in the CREATE TYPE statement.

Oracle 9i,differs from SQL:1999 in that if two methods have the same name but different signatures (i.e.number,types,and order of parameters)there is no overriding of the methods in Oracle9i.

Only methods that have been explicitly defined in the CREATE TYPE statement of a user-defined type can be used in SQL statements and stored procedures.

In client-server processing:

In SQL:1999,functions and procedures can overcome some of the limitations of SQL:1999 methods.

CLASS Employee { //Variables String LastName; String FirstName; Real HourlyRate; Integer HoursWorked; Date HireDate; String Job; //Methods Real Salary() ; String GetLastName() ; String GetFirstName() ; String GetJob() ;} -Which of the following is not part of the interface?

Which of the following requires object database technology?