ALTER Command:
(i) The ALTER command is used to alter the table structure like adding a column, renaming the existing column, change the data type of any column or size of the column or delete the column from the table. It is used in the following way:
(ii) ALTER TABLE <table-name>  ADD  <column-name><data type> <size>;
(iii) To add a new column "Address" of type 'char' to the Student table, the command is used as
(iv) ALTER TABLE Student ADD Address char;
To modify, existing column of table, the ALTER TABLE command can be used with MODIFY clause like wise:
(v) ALTER < table-name > MODIFY < column-name > < data type > < size >;
ALTER TABLE Student MODIFY Address char (25);
(vi) The above command will modify the address column of the Student table to now hold 25 characters.
(vii) The ALTER command can be used to rename an existing column in the following way:
(viii) ALTER < table-name > RENAME old-column- name TO new-column-name;
(ix) For example to rename the column Address to City, the command is used as :
(x) ALTER TABLE Student RENAME Address TO City;
(xi) The ALTER command can also be used to remove a column or all columns. for example to remove a particular column, the DROP COLUMN is used with the ALTER TABLE to remove a particular field, the command can be used as:
ALTER < table-name > DROP COLUMN < column-name >;
(xii) To remove the column City from the Student table, the command is used as :
ALTER TABLE Student DROP COLUMN City;

strl=' * '
i=1
while i< = 5:
print (strl*i)
i+=1

Program:
import matplotlib.pyplot as plt
sizes = [89, 80, 90, 100, 75]
labels = ["Tamil", "English", "Maths", "Science", "Social"]
plt.pie (sizes, labels = labels, autopct = "%.2f")
plt.axes( ).set aspect ("equal")
pIt.show ( )

# program to find fibonacci series
def fibo (n):
if n < = 1:
return n
else:
return (fibo (n - 1) + fibo (n - 2))
n = int (input ("Enter How manu terms"))
for i in range (n):
print (fibo (i))

//Now select File⟶New in Notepad and type the Python program
# Save the File as transpose.py. Program that compiles and executes a .cpp file
# Python tanspose.py -i trans_cpp
Python Program:
import sys, os, getopt
def main(argv):
cpp_file = "
exe_file = "
opts,args = getopt.getopt(argv, "i:",['ifile='])
for o, a in opts:
if o in ("-i", "< -ifile"):
cpp_file = a + '.cpp'
exe_file = a + '.exe'
run(cpp_file, exe_file)
defrun( cpp _file, exe_file):
print("Compiling" + cpp_file)
'os.system ('g++' + cpp_file + '-o' + exe_file)
print("Running" + exe_file)
print(" -------------------")
print
os.system( exe_file)
print
if __name__ =='__main__"
main( sys.argv[ 1:])

class test;
def check (self, num)
if num> 0:
print (num, "is positive number")
else:
print (num, "is negative number")
n = test ()
x = int (input("Enter the number"))
n. check (x)

for i in range (1,6):
for j in range (1, i+1)
print (i, end =' ')
print (end = '\n')
i+ = 1

import csv
csv.register_dialect('myDialect',delimiter = '|',skipinitialspace= True)
filename = 'c:\\pyprg\\ch13\\sample8.csv'
with open(filename, 'r') as csvfile:
reader = csv.DictReader(csvfile, dialect='myDialect')
for row in reader:
print(diet(row))
csvfile.close ( )

Import csv
#opening the csv file which is in different location with read mode
f=open("c:\\pyprg\\ch13ample5.csv",'r')
#reading the File with the help of csv.reader( )
readFile=csv.reader(f)
#printing the selected column
for col in readFile:
print col[0],col[3]
f.close ( )
Sample5.csv File in Excel

Program:
Num = []
for x in range(1, 11):
Num.append(x)
print("The list of numbers from 1 to 10 = ",Num)
for index, i in enumerate(Num):
if(i%2==0):
del Num[index]
print("The list after deleting even numbers = ", Num)
Output:
The list of numbers from 1 to 10 = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]
The list after deleting even numbers =. [1, 3, 5, 7, 9]

(i) In Python, 'for loop' is used to access all the elements in a list one by one. This is just like the for keyword in other programming language such as C++.
(ii) Syntax:
for index_var in list:
print (index_var)
(iii) Here, dex_var represents the index value of each element in the list. Python reads this "for" statement like English: "For (every) element in (the list of) list and print (the name of the) list items"
(iv) Example:
Marks=[23,45, 67, 78,98]
for x in Marks:
print(x)
Output:
23
45
67
78
98
(v) In the above example, Marks list has 5 elements; each element is indexed from 0 to 4.
(vi) The Python reads the for loop and print statements like English: "For (every) element (represented as (x) in (the list of) Marks and print (the values of the) elements.

(i) Computer resources are limited that should be utilized efficiently. The efficiency of an algorithm is defined as the number of computational resources used by the algorithm.
(ii) An algorithm must be analyzed to determine its resource usage. The efficiency of an algorithm can be measured based on the usage of different resources.
(iii) For maximum efficiency of algorithm we wish to minimize resource usage. The important resources such as time and space complexity cannot be compared directly, so time and space complexity could be considered for an algorithmic efficiency.
Method for determining Efficiency:
(i) The efficiency of an algorithm depends on how efficiently it uses time and memory space.
(ii) The time efficiency of an algorithm is measured by different factors. For example, write a program for a defined algorithm, execute it by using any programming language, and measure the total time it takes to run.
(iii) The execution time that you measure in this case would depend on a number of factors such as: -
1. Speed of the machine
2. Compiler and other system Software tools
3. Operating System
4. Programming language used
5. Volume of data required
(iv) However, to determine: how efficiently an algorithm solves a given problem, you would like to determine how the execution time is affected by the nature of the algorithm.
(v) Therefore, we need to develop fundamental laws that determine the efficiency of a program in terms of the nature of the underlying algorithm.

(i) Access control is a security technique that regulates who or what can view or use resources in a computing environment.
(ii) It is a fundamental concept in security that minimizes risk to the object.
(iii) In other words access control is a selective restriction of access to data. IN Object oriented programming languages it is implemented through access modifiers.
(iv) Classical object-oriented languages, such as C++ and Java. control the access to class members by public, private and protected keywords.
(v) Private members of a class are denied access from the outside the class. They can be handled only from within the class.
(vi) Public members (generally methods declared in a class) are accessible from outside the class. The object of the same class is required to invoke a public method. This arrangement of private instance variables and public methods ensures the principle of data encapsulation.
(vii) Protected members of a class are accessible from within the class and are also available to its sub-classes. No other process is permitted access to it. This enables specific resources of the parent class to be inherited by the child class.
(viii) Python doesn't have any mechanism that effectively restricts access to any instance variable or method. Python prescribes a convention of prefixing the name of the variable or method with single or double underscore to emulate the behaviour of protected and private access specifiers.
(ix) All members in a Python class are public by default. whereas by default in C++ and java they are private. Any member can be accessed from outside the class environment in Python which is not possible in C++ and java.

(i) The basic idea of data abstraction is to structure programs so that they operate on abstract data. That is, our programs should use data in such a way, as to make as few assumptions about the data as possible.
(li) At the same time, a concrete data representation is defined as an independent part of the program.
(iii) Any program consist of two parts. The two parts of a program are, the part that operates on abstract data and the part that defines a concrete representation, is connected by a small set of functions that implement abstract data in terms of the concrete representation.
(iv) To illustrate this technique, let us consider an example to design a set of functions for manipulating rational numbers.
(v) Example: A rational number is a ratio of integers, and rational numbers constitute an important sub-class of real numbers. A rational number such as 8/3 or 19/23 is typically written as : < numerator > /< denominator >
(vi) where both the < numerator > and <denominator> are placeholders for integer values. Both parts are needed to exactly characterize the value of the rational number. Actually dividing integers produces a float approximation, losing the exact precision of integers.
(vii) However, you can create an exact representation for rational numbers by combining together the numerator and denominator.
(viii) As we know from using functional abstractions, we can start programming productively before you have an implementation of some parts of our program.
(ix) Let us begin by assuming that you already have a way of constructing a rational number from a numerator and a denominator. You also assume that, given a rational number, you have a way of selecting its numerator and its denominator component.