Connect to TiDB with PyMySQL

TiDB is a MySQL-compatible database, and PyMySQL is a popular open-source driver for Python.

In this tutorial, you can learn how to use TiDB and PyMySQL to accomplish the following tasks:

• Set up your environment.
• Connect to your TiDB cluster using PyMySQL.
• Build and run your application. Optionally, you can find sample code snippets for basic CRUD operations.

Prerequisites

To complete this tutorial, you need:

• Python 3.8 or higher.
• Git.
• A TiDB cluster.

If you don't have a TiDB cluster, you can create one as follows:

• (Recommended) Follow Creating a TiDB Cloud Serverless cluster to create your own TiDB Cloud cluster.
• Follow Deploy a local test TiDB cluster or Deploy a production TiDB cluster to create a local cluster.

Run the sample app to connect to TiDB

This section demonstrates how to run the sample application code and connect to TiDB.

Step 1: Clone the sample app repository

Run the following commands in your terminal window to clone the sample code repository:

git clone https://github.com/tidb-samples/tidb-python-pymysql-quickstart.git
cd tidb-python-pymysql-quickstart

Step 2: Install dependencies

Run the following command to install the required packages (including PyMySQL) for the sample app:

pip install -r requirements.txt

Step 3: Configure connection information

Connect to your TiDB cluster depending on the TiDB deployment option you've selected.

• TiDB Cloud Serverless
• TiDB Cloud Dedicated
• TiDB Self-Managed

Step 4: Run the code and check the result

1. Execute the following command to run the sample code:

   python pymysql_example.py
   

2. Check the Expected-Output.txt to see if the output matches.

Sample code snippets

You can refer to the following sample code snippets to complete your own application development.

For complete sample code and how to run it, check out the tidb-samples/tidb-python-pymysql-quickstart repository.

Connect to TiDB

from pymysql import Connection
from pymysql.cursors import DictCursor


def get_connection(autocommit: bool = True) -> Connection:
    config = Config()
    db_conf = {
        "host": ${tidb_host},
        "port": ${tidb_port},
        "user": ${tidb_user},
        "password": ${tidb_password},
        "database": ${tidb_db_name},
        "autocommit": autocommit,
        "cursorclass": DictCursor,
    }

    if ${ca_path}:
        db_conf["ssl_verify_cert"] = True
        db_conf["ssl_verify_identity"] = True
        db_conf["ssl_ca"] = ${ca_path}

    return pymysql.connect(**db_conf)

When using this function, you need to replace ${tidb_host}, ${tidb_port}, ${tidb_user}, ${tidb_password}, ${tidb_db_name} and ${ca_path} with the actual values of your TiDB cluster.

Insert data

with get_connection(autocommit=True) as conn:
    with conn.cursor() as cur:
        player = ("1", 1, 1)
        cursor.execute("INSERT INTO players (id, coins, goods) VALUES (%s, %s, %s)", player)

For more information, refer to Insert data.

Query data

with get_connection(autocommit=True) as conn:
    with conn.cursor() as cur:
        cur.execute("SELECT count(*) FROM players")
        print(cursor.fetchone()["count(*)"])

For more information, refer to Query data.

Update data

with get_connection(autocommit=True) as conn:
    with conn.cursor() as cur:
        player_id, amount, price="1", 10, 500
        cursor.execute(
            "UPDATE players SET goods = goods + %s, coins = coins + %s WHERE id = %s",
            (-amount, price, player_id),
        )

For more information, refer to Update data.

Delete data

with get_connection(autocommit=True) as conn:
    with conn.cursor() as cur:
        player_id = "1"
        cursor.execute("DELETE FROM players WHERE id = %s", (player_id,))

For more information, refer to Delete data.

Useful notes

Using driver or ORM framework?

The Python driver provides low-level access to the database, but it requires the developers to:

• Manually establish and release database connections.
• Manually manage database transactions.
• Manually map data rows (represented as a tuple or dict in pymysql) to data objects.

Unless you need to write complex SQL statements, it is recommended to use ORM framework for development, such as SQLAlchemy, Peewee, and Django ORM. It can help you:

• Reduce boilerplate code for managing connections and transactions.
• Manipulate data with data objects instead of a number of SQL statements.

Next steps

• Learn more usage of PyMySQL from the documentation of PyMySQL.
• Learn the best practices for TiDB application development with the chapters in the Developer guide, such as Insert data, Update data, Delete data, Single table reading, Transactions, and SQL performance optimization.
• Learn through the professional TiDB developer courses and earn TiDB certifications after passing the exam.

Need help?

Ask the community on Discord or Slack, or submit a support ticket.