No connection to MySQL-database - PythonAnywhere/ Beginners Plan

Question

Attempt to connect to MySQL-database by module MySQLdb fails and will be responded by: name 'MySQLdb' is not defined... in the servers log. Environment is not virtual, framework is Flask

The connection attempt via MySQLdb.connect(<credentials>) is in a try/except-clause and an exception will be thrown. In order to verify the correct credentials I entered host/user/password/database in the bash-console and the connect-function returned True for connect-state (=connected). But when running this in the Flask-App, then the server returns the above error message.

from flask import Flask
try:
    import MySQLdb
except Exception as e:
    print("A problem with import MySQLdb......", e)

def checkDBConnection():
    try:
        cnx = MySQLdb.connect(
        host = '<myUserName>.mysql.eu.pythonanywhere-services.com',
        user = '<myUserName>',
        password = '<myPW>',
        database = '<userName>$sensorData'
        )
        return True
    except Exception as e:
        print("Database error: ", e)
        return False

app = Flask(__name__)
#application = Flask(__name__)   # see hint in *.wsgi file

@app.route("/sensorData/<val>")
def storeDB(val):
    #return f'val is: {val}'
    check = checkDBConnection()
    if check:
        return "<p>Database access successful...........</p>"
        # Closing Database Connection
        #cnx.close()
    else:
        return "<p>Connection failed ......</p>"

Pleas show all the error messages that you see. Are you sure that MySQLdb has been installed correctly? — OldBoy
– OldBoy, Commented Jun 13 at 9:41
The MySQL-python package (MySQLdb) is no longer compatible with Python 3.x. To better assist you, please share more logs or error messages so the community can help troubleshoot further. — Gireesh d
– Gireesh d, Commented Jun 13 at 9:43
The MySQLdb package has not been updated since 2014, so i suspect it is no longer maintained. I suggest you switch to mysql-connector-python 9.3.0 which is up to date. — OldBoy
– OldBoy, Commented Jun 13 at 9:45
This question is similar to: No module named MySQLdb. If you believe it’s different, please edit the question, make it clear how it’s different and/or how the answers on that question are not helpful for your problem. (the top-scored answer is Pyhton2, but a number of the other high-scoring answers cover Python 3) — snakecharmerb
– snakecharmerb, Commented Jun 13 at 11:24

Gireesh d · Accepted Answer · 2025-06-13 09:56:30Z

2

The error you're seeing is likely because you're using MySQL-python (which provides MySQLdb), but that package does not support Python 3 — it's only compatible with Python 2.x and is no longer maintained.

✅ Solution:

You can install pymysql and cryptography (needed for secure auth plugins like sha256_password or caching_sha2_password) with:

python3 -m pip install pymysql cryptography

Then, in your Python code, do the following to make pymysql act like MySQLdb:

import pymysql 
pymysql.install_as_MySQLdb()

This allows frameworks or codebases expecting MySQLdb to work seamlessly with pymysql. pymysql.install_as_MySQLdb() monkey-patches sys.modules to alias MySQLdb to pymysql.

answered Jun 13 at 9:56

Gireesh d

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