This document discusses connecting to and querying databases in Python. It outlines 7 steps to connect to a MySQL database: 1) start Python, 2) import database packages, 3) open a connection, 4) create a cursor, 5) execute queries, 6) extract data, and 7) clean up. It provides examples of connecting to MySQL and retrieving the first 3 rows from a student table.

1. Python Database
Connectivity

2. Introduction
• Python is a high-level, general-purpose, and very popular
programming language.
• Python can be used in database applications.
• One of the most popular databases is MySQL.

3. Python DB Connectivity

4. Steps for Creating Database Connectivity
Step 1: Start Python
Step 2: Import the packages required for database programming
Step 3:Open a connection to database
Step 4:Create a cursor instance
Step 5:Execute a query
Step 6:Extract data from result set
Step 7:Clean up the environment

5. Step 1: Start Python
• Start Python editor – IDLE or any Python Editor

6. Step 2: Import the packages required for
database programming
import mysql.connector
Example:
import mysql.connector

7. Step 3:Open a connection to database
syntax :connect()
Connection-Object= mysql.connector.connect(host = <host-
name> , user = <username> , passwd = <password>[,database=,
database name>] )
Example:
#Create the connection object
mycon = mysql.connector.connect(host = "localhost", user = "roo
t",passwd = "google", database = "mydb")

8. Step 4:Create a cursor instance
<cursor-object> = connectionobject.cursor()
Example:
cursor1 = mycon.cursor()

9. Cursor
Cursor is a Temporary Memory or Temporary Work Station.
It is Allocated by Database Server at the Time of Performing
DML(Data Manipulation Language) operations on Table by User.
Cursors are used to store Database Tables.

10. Step 5:Execute a query
Syntax:
<cursor-object>.execute(<sql query>)
Example:
cursor1.execute(“select * from data”)

11. Step 6:Extract data from result set
*fetchall
*fetchone
*fetchmany
*rowcount
Example:
data = cursor1.fetchall()
count = cursor1.rowcount
for row in data:
print(row)

12. Step 7:Clean up the environment
<connection object>.close()
Example:
mycon.close()

13. Write a python program to display first 3 rows
from student table of Mysql database.
import mysql.connector
mycon = mysql.connector.connect(host = “localhost”,
user = “root”,
password = “sample”,
database = “test”)
cursor1 = mycon.cursor()
cursor1.execute(“select * from student”)
data = cursor1.fetchmany(3)
count = cursor1.rowcount
for row in data:
print(row)
mycon.close()

14. Output
(1,’Arun’,90)
(2,’balu’,80)
(3,’siva’,95)