DatabaseManagementSystems/Practical/Practical Exam/Connectivity/C2 - MySQL Connectivity.md

C1 - MySQL Connectivity

Problem Statement: Implement MYSQL/Oracle database connectivity with PHP /python /Java Implement Database navigation operations (add, delete, edit,).

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Pre-requisites (with installation command for Ubuntu):

1. Python3 - sudo apt install python3
2. pip - sudo apt install pip
3. mysql-connector - pip3 install mysql-connector OR pip3 install mysql-connector --break-system-packages (installs it system-wide)

Instructions

1. First, open the Terminal and log in to MySQL:

mysql -u root -p

Note

Usually the password in our labs is root. If you don't know the password, try running sudo mysql. This will run the mysql command as root.

2. Whether you logged in as root or not, run this command to set the password for root user in mysql which is required for connecting to the database:

ALTER USER 'root'@'localhost' IDENTIFIED WITH mysql_native_password BY 'root';
FLUSH PRIVILEGES;

3. Now, in MySQL we need to initialize the database and tables:

-- Creating the database
CREATE DATABASE connectMe;
USE connectMe;

-- Creating a table
CREATE TABLE students (
  roll INT,
  name VARCHAR(255)
);

-- Exit
exit

We need to exit from MySQL shell since the work there is done for now.

5. Create a new file connectSQL.py with the following contents:

import mysql.connector
# Connecting to MySQL database
db = mysql.connector.connect(
  host="localhost",
  user="root",
  password="root", # Password of root user we set in step 2
  database="connectMe" # Name of the database we created in step 3
)

Cursor = db.cursor()

sqlInsert = "INSERT INTO students (roll, name) VALUES (21, 'Stewie')" # insert operation
Cursor.execute(sqlInsert)
print(Cursor.rowcount, "record added to database.")

Cursor.execute(sqlInsert)
sqlInsert = "INSERT INTO students (roll, name) VALUES (22, 'Foxy')" # insert operation
print(Cursor.rowcount, "record added to database.")

sqlUpdate = "UPDATE students SET roll = 21  WHERE roll = 20"
Cursor.execute(sqlUpdate)
print(Cursor.rowcount, "record updated.")

sqlDelete = "DELETE FROM students WHERE roll = 20"
Cursor.execute(sqlDelete)
print(Cursor.rowcount, "record deleted.")

db.commit()
Cursor.close()
db.close()

6. Open Terminal and run the above program:

python3 connectSQL.py

Note

This step assume you have stored the file in home directory or you know how to change the current working directory.

7. That's it! You can view the changes in MySQL by logging in using mysql -u root -p (Password: root) and viewing the table:

USE connectMe;
SELECT * FROM students;

Warning

Never use root as password in production. Use a strong password. This guide uses root as password for simplicity and educational purposes.

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