Commerce (English Medium) Class 12 - CBSE Question Bank Solutions

Quickdev, an IT based firm, located in Delhi is planning to set up network for its four branches within a city with its Marketing department in Kanpur. As a network professional, give solution to the questions, after going through the branches locations and other details which are given below: 

Distance between various branches is a follows:

Number of computers in each of the branches:

1. Suggest the most suitable place to install the server for the Delhi branch with a suitable reason.
2. Suggest an ideal layout for connecting all these branches within Delhi.
3. Which device will you suggest, that should be placed in each of these branches to efficiently connect all the computers within these branches?
4. Delhi firm is planning to connect to its Marketing department in Kanpur which is approximately 300 km away. Which type of network out of LAN, WAN, or MAN will be formed? Justify your answer.
5. Suggest a protocol that shall be needed to provide help for transferring of files between Delhi and Kanpur branch.

The modem at the sender’s computer end acts as a ______.

What is the use of a raise statement? Write a code to accept two numbers and display the quotient. Appropriate exception should be raised if the user enters the second number (denominator) as zero (0).

Differentiate between readline() and readlines().

Write the use and syntax for the following method:

read()

Use assert statement in Question No. 3 to test the division expression in the program.

Why foreign keys are allowed to have NULL values? Explain with an example.

Differentiate between Primary key and foreign key.

A school has a rule that each student must participate in a sports activity. So each one should give only one preference for sports activity. Suppose there are five students in a class, each having a unique roll number. The class representative has prepared a list of sports preferences as shown below. Answer the following:

1. Roll no 24 may not be interested in sports. Can a NULL value be assigned to that student’s preference field?
2. Roll no 17 has given two preference sports. Which property of relational DBMC is violated here? Can we use any constraint or key in the relational DBMS to check against such violations, if any?
3. Kabaddi was not chosen by any student. Is it possible to have this tuple in the Sports Preferences relation?

The school canteen wants to maintain records of items available in the school canteen and generate bills when students purchase any item from the canteen. The school wants to create a canteen database to keep track of items in the canteen and the items purchased by students. Design a database by answering the following question:

In order to generate the bill, we should know the quantity of an item purchased. Should this information be in a new relation or a part of the previous relation? If a new relationship is required, decide the appropriate name and data type for attributes. Also, identify the appropriate primary key and foreign key so that the following two restrictions are satisfied:

1. The same bill cannot be generated for different orders.
2. Bill can be generated only for available items in the canteen.

An organisation wants to create a database EMPDEPENDENT to maintain the following details about its employees and their dependent.

EMPLOYEE(AadharNumber, Name, Address, Department, EmployeeID)
DEPENDENT(EmployeeID, DependentName, Relationship)

1. Name the attributes of EMPLOYEE, which can be used as candidate keys.
2. The company wants to retrieve details of the dependent of a particular employee. Name the tables and the key which are required to retrieve this detail.
3. What is the degree of EMPLOYEE and DEPENDENT relation?

An organisation wants to create a database EMPDEPENDENT to maintain the following details about its employees and their dependent.

EMPLOYEE(AadharNumber, Name, Address, Department, EmployeeID)
DEPENDENT(EmployeeID, DependentName, Relationship)

The company wants to retrieve details of the dependent of a particular employee. Name the tables and the key which are required to retrieve this detail.

In a multiplex, movies are screened in different auditoriums. One movie can be shown in more than one auditorium. In order to maintain the record of movies, the multiplex maintains a relational database consisting of two relations viz. MOVIE and AUDI respectively as shown below:

Movie(Movie_ID, MovieName, ReleaseDate) Audi(AudiNo, Movie_ID, Seats, ScreenType, TicketPrice)

Is it correct to assign Movie_ID as the primary key in the MOVIE relation? If no, then suggest an appropriate primary key.

In a multiplex, movies are screened in different auditoriums. One movie can be shown in more than one auditorium. In order to maintain the record of movies, the multiplex maintains a relational database consisting of two relations viz. MOVIE and AUDI respectively as shown below:

Movie(Movie_ID, MovieName, ReleaseDate) Audi(AudiNo, Movie_ID, Seats, ScreenType, TicketPrice)

Is it correct to assign AudiNo as the primary key in the AUDI relation? If no, then suggest an appropriate primary key.

In a multiplex, movies are screened in different auditoriums. One movie can be shown in more than one auditorium. In order to maintain the record of movies, the multiplex maintains a relational database consisting of two relations viz. MOVIE and AUDI respectively as shown below:

Movie(Movie_ID, MovieName, ReleaseDate) Audi(AudiNo, Movie_ID, Seats, ScreenType, TicketPrice)

1. Is it correct to assign Movie_ID as the primary key in the MOVIE relation? If no, then suggest an appropriate primary key.
2. Is it correct to assign AudiNo as the primary key in the AUDI relation? If no, then suggest an appropriate primary key.
3. Is there any foreign key in any of these relations?

1. Name the primary key of each table.
2. Find foreign key(s) in table PROJECT-ASSIGNED.
3. Is there any alternate key in table STUDENT? Give justification for your answer.
4. Can a user assign duplicate value to the field RollNo of STUDENT table? Justify.

For the above-given database STUDENT-PROJECT, can we perform the following operation?

Insert a student record with a missing registration number value.

Write the output produced by the following SQL statement:

SELECT POW(2, 3);

Consider the following MOVIE table and write the SQL query based on it.

1. Display all the information from the Movie table.
2. List business is done by the movies showing only MovieID, MovieName, and Total_Earning. Total_ Earning to be calculated as the sum of ProductionCost and BusinessCost.
3. List the different categories of movies.
4. Find the net profit of each movie showing its MovieID, MovieName, and NetProfit. Net Profit is to be calculated as the difference between Business Cost and Production Cost.
5. List MovieID, MovieName, and Cost for all movies with ProductionCost greater than 10,000 and less than 1,00,000.
6. List details of all movies which fall in the category of comedy or action.
7. List details of all movies which have not been released yet.