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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:

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

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

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 Serverless
  • TiDB Dedicated
  • TiDB Self-Hosted
  1. Navigate to the Clusters page, and then click the name of your target cluster to go to its overview page.

  2. Click Connect in the upper-right corner. A connection dialog is displayed.

  3. Ensure the configurations in the connection dialog match your operating environment.

    • Endpoint Type is set to Public
    • Connect With is set to General
    • Operating System matches your environment.
  4. Click Create password to create a random password.

  5. Run the following command to copy .env.example and rename it to .env:

    cp .env.example .env
  6. Copy and paste the corresponding connection string into the .env file. The example result is as follows:

    TIDB_HOST='{host}' # e.g. gateway01.ap-northeast-1.prod.aws.tidbcloud.com TIDB_PORT='4000' TIDB_USER='{user}' # e.g. xxxxxx.root TIDB_PASSWORD='{password}' TIDB_DB_NAME='test' CA_PATH='{ssl_ca}' # e.g. /etc/ssl/certs/ca-certificates.crt (Debian / Ubuntu / Arch)

    Be sure to replace the placeholders {} with the connection parameters obtained from the connection dialog.

  7. Save the .env file.

  1. Navigate to the Clusters page, and then click the name of your target cluster to go to its overview page.

  2. Click Connect in the upper-right corner. A connection dialog is displayed.

  3. Click Allow Access from Anywhere and then click Download TiDB cluster CA to download the CA certificate.

    For more details about how to obtain the connection string, refer to TiDB Dedicated standard connection.

  4. Run the following command to copy .env.example and rename it to .env:

    cp .env.example .env
  5. Copy and paste the corresponding connection string into the .env file. The example result is as follows:

    TIDB_HOST='{host}' # e.g. tidb.xxxx.clusters.tidb-cloud.com TIDB_PORT='4000' TIDB_USER='{user}' # e.g. root TIDB_PASSWORD='{password}' TIDB_DB_NAME='test' CA_PATH='{your-downloaded-ca-path}'

    Be sure to replace the placeholders {} with the connection parameters obtained from the connection dialog, and configure CA_PATH with the certificate path downloaded in the previous step.

  6. Save the .env file.

  1. Run the following command to copy .env.example and rename it to .env:

    cp .env.example .env
  2. Copy and paste the corresponding connection string into the .env file. The example result is as follows:

    TIDB_HOST='{tidb_server_host}' TIDB_PORT='4000' TIDB_USER='root' TIDB_PASSWORD='{password}' TIDB_DB_NAME='test'

    Be sure to replace the placeholders {} with the connection parameters, and remove the CA_PATH line. If you are running TiDB locally, the default host address is 127.0.0.1, and the password is empty.

  3. Save the .env file.

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

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