Connecting to TiDB with mysqljs/mysql driver

TiDB is a MySQL-compatible database, and mysqljs/mysql is a pure node.js JavaScript Client implementing the MySQL protocol for the database connection and SQL operations.

The following guide will show you how to connect to the TiDB cluster with Node.js mysqljs/mysql driver and perform basic SQL operations like create, read, update, and delete.

Note

To connect to a TiDB Serverless cluster with public endpoint, you MUST enable TLS connection on the node-mysql driver.

Prerequisites

To complete this guide, you need:

Node.js >= 16.x installed on your machine
Git installed on your machine
A TiDB cluster running

If you don't have a TiDB cluster yet, please create one with one of the following methods:

(Recommend) Start up a TiDB Serverless cluster instantly with a few clicks on TiDB Cloud.
Start up a TiDB Playground cluster with TiUP CLI on your local machine.

Getting started

This section demonstrates how to run the sample application code and connect to TiDB with Node.js mysqljs/mysql driver.

1. Clone the repository

Run the following command to clone the sample code locally：

git clone https://github.com/tidb-samples/tidb-nodejs-mysqljs-quickstart.git
cd tidb-nodejs-mysqljs-quickstart

2. Install dependencies

Run the following command to install the dependencies (including the mysql package) required by the sample code：

npm install

Install dependencies to existing project

For your existing project, run the following command to install the packages:

mysql: A pure node.js JavaScript Client implementing the MySQL protocol for the database connection and SQL operations.
dotenv: The utils package to loading environment variables from the .env file.

npm install mysql dotenv --save

Step 3. Provide connection parameters

(Option 1) TiDB Serverless

Navigate to the Clusters page, and then click the name of your target cluster to go to its overview page.
Click Connect in the upper-right corner.
In the connection dialog, select General from the Connect With dropdown and keep the default setting of the Endpoint Type as Public.
If you have not set a password yet, click Create password to generate a random password.

The connection dialog of TiDB Serverless
Make a copy of the .env.example file to the .env file:
```
cp .env.example .env
```
Edit the .env file, copy the connection parameters on the connection dialog, and replace the corresponding placeholders {}. The example configuration is as follows:
```
TIDB_HOST={host}
TIDB_PORT=4000
TIDB_USER={user}
TIDB_PASSWORD={password}
TIDB_DATABASE=test
TIDB_ENABLE_SSL=true
```
Modify TIDB_ENABLE_SSL to true to enable a TLS connection. (Required for public endpoint)

(Option 2) TiDB Dedicated

You can obtain the database connection parameters on TiDB Cloud's Web Console through the following steps:

Navigate to the Clusters page, and then click the name of your target cluster to go to its overview page.
Click Connect in the upper-right corner. A connection dialog is displayed.
Click Allow Access from Anywhere, and then click Download TiDB cluster CA to download the CA certificate.
Select General from the Connect With dropdown and select Public from the Endpoint Type dropdown.
Run the following command to copy .env.example and rename it to .env:
```
cp .env.example .env
```
Edit the .env file, copy the connection parameters on the connection dialog, and replace the corresponding placeholders {}. The example configuration is as follows:
```
TIDB_HOST=<host>
TIDB_PORT=4000
TIDB_USER=<user>
TIDB_PASSWORD=<password>
TIDB_DATABASE=test
TIDB_ENABLE_SSL=true
TIDB_CA_PATH=/path/to/ca.pem
```
Modify TIDB_ENABLE_SSL to true to enable a TLS connection and using TIDB_CA_PATH to specify the file path of CA certificate downloaded from the connection dialog.

(Option 3) TiDB Self-Hosted

Make a copy of the .env.example file to the .env file.
```
cp .env.example .env
```
Replace the placeholders for <host>, <user>, and <password> with the connection parameters of your TiDB cluster.
```
TIDB_HOST=<host>
TIDB_PORT=4000
TIDB_USER=<user>
TIDB_PASSWORD=<password>
TIDB_DATABASE=test
# TIDB_ENABLE_SSL=true
# TIDB_CA_PATH=/path/to/ca.pem
```
The TiDB Self-Hosted cluster using non-encrypted connection between TiDB's server and clients by default.

If you want to enable TLS connection, please uncomment the TIDB_ENABLE_SSL and TIDB_CA_PATH options and specify the file path of CA certificate defined with ssl-ca option.

Step 4. Run the sample code

Run the following command to execute the sample code:

npm start

Expected execution output:

If the connection is successful, the console will output the version of the TiDB cluster.

🔌 Connected to TiDB cluster! (TiDB version: 5.7.25-TiDB-v7.1.0)
⏳ Loading sample game data...
✅ Loaded sample game data.

🆕 Created a new player with ID 12.
ℹ️ Got Player 12: Player { id: 12, coins: 100, goods: 100 }
🔢 Added 50 coins and 50 goods to player 12, updated 1 row.
🚮 Deleted 1 player data.

Sample code snippets

Connect with connection options

The following code establish a connection to TiDB with options defined in environment variables:

// Step 1. Import the 'mysql' and 'dotenv' packages.
import { createConnection } from "mysql";
import dotenv from "dotenv";
import * as fs from "fs";

// Step 2. Load environment variables from .env file to process.env.
dotenv.config();

// Step 3. Create a connection with the TiDB cluster.
const options = {
    host: process.env.TIDB_HOST || '127.0.0.1',
    port: process.env.TIDB_PORT || 4000,
    user: process.env.TIDB_USER || 'root',
    password: process.env.TIDB_PASSWORD || '',
    database: process.env.TIDB_DATABASE || 'test',
    ssl: process.env.TIDB_ENABLE_SSL === 'true' ? {
        minVersion: 'TLSv1.2',
        ca: process.env.TIDB_CA_PATH ? fs.readFileSync(process.env.TIDB_CA_PATH) : undefined
    } : null,
}
const conn = createConnection(options);

// Step 4. Perform some SQL operations...

// Step 5. Close the connection.
conn.end();

For TiDB Serverless, TLS connection MUST be enabled via TIDB_ENABLE_SSL when using public endpoint, but you don't have to specify an SSL CA certificate via TIDB_CA_PATH, because Node.js uses the built-in Mozilla CA certificate by default, which is trusted by TiDB Serverless.

Insert data

The following query creates a single Player record and returns a ResultSetHeader object:

conn.query('INSERT INTO players (coins, goods) VALUES (?, ?);', [coins, goods], (err, ok) => {
   if (err) {
       console.error(err);
   } else {
       console.log(ok.insertId);
   }
});

For more information, refer to Insert data.

Query data

The following query returns a single Player record by ID 1:

conn.query('SELECT id, coins, goods FROM players WHERE id = ?;', [id], (err, rows) => {
    if (err) {
        console.error(err);
    } else {
        console.log(rows[0]);
    }
});

For more information, refer to Query data.

Update data

The following query adds 50 coins and 50 goods to the Player with ID 1:

conn.query(
   'UPDATE players SET coins = coins + ?, goods = goods + ? WHERE id = ?;',
   [incCoins, incGoods, playerID],
   (err, ok) => {
      if (err) {
         console.error(err);
      } else {
          console.log(ok.affectedRows);
      }
   }
);

For more information, refer to Update data.

Delete data

The following query deletes the Player record with ID 1:

async function deletePlayerByID(conn, id) {
    return new Promise((resolve, reject) => {
        conn.query('DELETE FROM players WHERE id = ?;', [id], (err, ok) => {
            if (err) {
                reject(err);
            } else {
                resolve(ok.affectedRows);
            }
        });
    });
}

For more information, refer to Delete data.

Best practices

Using connection pools to manage database connections, which can reduce the performance overhead caused by frequently establishing/destroying connections.
Escaping query values before executing SQL statements to prevent SQL injection attacks.

Notice: The mysqljs/mysql package does not yet support prepared statements, it only escapes values on the client side (related issue: mysqljs/mysql#274). If you want to use this feature to avoid SQL injection or improve efficiency of batch insert/update, it is recommended to use mysql2 package instead.
Using ORM frameworks to improve development efficiency in scenarios without a number of complex SQL statements, such as: Sequelize, TypeORM, and Prisma.
Enable the supportBigNumbers: true option when dealing with big numbers (BIGINT and DECIMAL columns) in the database.

What's next

Check out the documentation of mysqljs/mysql for more usage about the driver.
Explore the real-time analytics feature on the TiDB Cloud Playground.
Read the TiDB Developer Guide to learn more details about application development with TiDB.

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