Arts (English Medium) Class 12 - CBSE Question Bank Solutions for Computer Science (Python)

Using the sports database containing two relations (TEAM, MATCH_DETAILS) and write the Query for the following:

Display the MatchID of matches played by Team 2 and not won by it.

What are the risks associated with HTTP? How can we resolve these risks by using HTTPS?

Which of the following mode in the file opening statement results or generates an error if the file does not exist?

The SELECT statement when combined with the ______ clause returns records without repetition.

Write two points of difference between Circuit Switching and Packet Switching.

Explain the use of ‘Foreign Key’ in a Relational Database Management System. Give example to support your answer.

Consider the following tables – Bank_Account and Branch:

Table: Bank_Account

Table: Branch

What will be the output of the following statement?

SELECT * FROM Bank_Account NATURAL JOIN Branch;

Write a method COUNTLINES() in Python to read lines from the text file ‘TESTFILE.TXT’ and display the lines which do not start with any vowel.

Example:

If the file content is as follows:

An apple a day keeps the doctor away.
We all pray for everyone’s safety.
A marked difference will come in our country.

The COUNTLINES() function should display the output as:

The number of lines not starting with any vowel - 1

Write a function ETCount() in Python, which should read each character of a text file “TESTFILE.TXT” and then count and display the count of occurrence of alphabets E and T individually (including small cases e and t too).

Example:

If the file content is as follows:

Today is a pleasant day.
It might rain today.
It is mentioned on weather sites

The ETCount() function should display the output as:
E or e : 6
T or t : 9

______ clause is used with a SELECT statement to display data in a sorted form with respect to a specified column.

Explain the concept of “Alternate Key” in a Relational Database Management System with an appropriate example.

Write the output of the queries (i) to (iv) based on the table, WORKER given below:

TABLE: WORKER

1. SELECT F_NAME, CITY FROM WORKER ORDER BY STATE DESC;
2. SELECT DISTINCT (CITY) FROM WORKER;
3. SELECT F_NAME, STATE FROM WORKER WHERE L_NAME LIKE '_HA%';
4. SELECT CITY, COUNT(*) FROM WORKER GROUP BY CITY;

Write the definition of a Python function named LongLines() which reads the contents of a text file named 'LINES.TXT' and displays those lines from the file which have at least 10 words in it. For example, if the content of 'LINES.TXT' is as follows: 

Once upon a time, there was a woodcutter
He lived in a little house in a beautiful, green wood.
One day, he was merrily chopping some wood.
He saw a little girl skipping through the woods, whistling happily.
The girl was followed by a big gray wolf. 

Then the function should display output as:

He lived in a little house in a beautiful, green wood.
He saw a little girl skipping through the woods, whistling happily.

Write a function count_Dwords() in Python to count the words ending with a digit in a text file "Details.txt".

Example:
If the file content is as follows:
On seat2 V1P1 will sit and
On seat1 VVIP2 will be sitting
The output will be:
The number of words ending with a digit is 4

Write the outputs of the SQL queries (i) to (iv) based on the relations COMPUTER and SALES given below:

1. SELECT MIN(PRICE), MAX(PRICE) FROM COMPUTER;
2. SELECT COMPANY, COUNT(*) FROM COMPUTER GROUP BY COMPANY HAVING COUNT(COMPANY) > 1;
3. SELECT PROD_NAME, QTY_SOLD FROM COMPUTER C, SALES S WHERE C.PROD_ID=S.PROD_ID AND TYPE = 'INPUT';
4. SELECT PROD_NAME, COMPANY, QUARTER FROM COMPUTER C, SALES S WHERE C.PROD_ID=S.PROD_ID;

The code given below reads the following records from the table employee and displays only those records that have employees coming from the city 'Delhi':

E_code - String
E_name - String
Sal - Integer
City - String

Note the following to establish connectivity between Python and MySQL:

• Username is root
• Password is root
• The table exists in a MySQL database named emp.
• The details (E_code,E_name,Sal,City) are the attributes of the table.

Write the following statements to complete the code:

Statement 1 - to import the desired library.

Statement 2 - to execute the query that fetches records of the employees/coming from the city ‘Delhi’.

Statement 3 - to read the complete data of the query (rows whose city is Delhi) into the object named details, from the table employee in the database.

import ____________ as mysql  #Statement 1
def display():
   mydb=mysql.connect(host="localhost",user="root"
   passwd="root", database=" emp")
   mycursor=mydb.cursor()
   ____________ #Statement 2
   details = ____________ # Statement 3
   for i in details:
       print (i)

The school has asked their estate manager Mr Rahul to maintain the data of all the labs in a table LAB. Rahul has created a table and entered data from 5 labs.

Based on the data given above answer the following questions:

(i) Identify the columns which can be considered as Candidate keys.

(ii) Write the degree and cardinality of the table.

(iii) Write the statements to:

      (a) Insert a new row with appropriate data.

      (b) Increase the capacity of all the labs by 10 students which are on
           the 'I' Floor.

                                     OR

(iii) Write the statements to:

        (a) Add a constraints PRIMARY KEY to the column LABNO in the table.

        (b) Delete the table LAB.

Which of the following statements is FALSE about keys in a relational database?

In case of ______ switching, before a communication starts, a dedicated path is identified between the sender and the receiver.

Write a function, lenWords(STRING), that takes a string as an argument and returns a tuple containing length of each word of a string.
For example, if the string is "Come let us have some fun", the tuple will have (4, 3, 2, 4, 4, 3)