MySQL Database Connection - Python

import mysql.connector
from mysql.connector import Error
import sys

def connect_to_mysql(host='localhost', database='school_db', 
                   user='root', password='password'):
    """
    Connect to MySQL database with error handling

    Args:
        host (str): MySQL server host
        database (str): Database name
        user (str): Username
        password (str): Password

    Returns:
        tuple: (connection, error_message)
    """
    connection = None

    try:
        connection = mysql.connector.connect(
            host=host,
            database=database,
            user=user,
            password=password
        )

        if connection.is_connected():
            print(f"✅ Connected to MySQL database '{database}'")
            return connection, None

    except Error as e:
        error_msg = f"❌ Error connecting to MySQL: {e}"
        print(error_msg)
        return None, error_msg

    return connection, None

def test_connection(connection):
    """Test if connection is active"""
    if connection and connection.is_connected():
        cursor = connection.cursor()
        cursor.execute("SELECT DATABASE()")
        db_name = cursor.fetchone()
        print(f"📊 Current database: {db_name[0]}")
        cursor.close()
        return True
    return False

def close_connection(connection):
    """Safely close database connection"""
    if connection and connection.is_connected():
        connection.close()
        print("🔌 MySQL connection closed")

# Usage Example
if __name__ == "__main__":
    # Connect to database
    conn, error = connect_to_mysql()

    if conn:
        # Test connection
        test_connection(conn)

        # Your database operations here

        # Close connection
        close_connection(conn)
    else:
        print(f"Connection failed: {error}")
        sys.exit(1)

🛠️ Common Connection Parameters

Parameter	Example	Description
host	'localhost'	MySQL server address
database	'school_db'	Database name to connect
user	'root'	MySQL username
password	'password'	MySQL password
port	3306	MySQL port (optional)

🔧 Connection String Variations

With Port

connection = mysql.connector.connect(
    host='localhost',
    port=3306,
    database='school_db',
    user='root',
    password='password'
)

Remote Database

connection = mysql.connector.connect(
    host='your-server.com',
    database='production_db',
    user='app_user',
    password='secure_password'
)

⚠️ Common Errors & Solutions

Error	Cause	Solution
Access denied for user	Wrong username/password	Check credentials
Can't connect to MySQL server	Server not running	Start MySQL service
Unknown database	Database doesn't exist	Create database first
Connection timeout	Network/firewall issues	Check firewall settings

📚 Installation

# Install MySQL connector
pip install mysql-connector-python

# Alternative: PyMySQL
pip install pymysql

---

📚 Learn Database Theory →