MySQL Guide

MySQLClient is the direct MySQL client for LinkedQL. It gives you full SQL access and transactions over a native MySQL connection, with planned realtime capabilities built on MySQL's binlog.

Use MySQLClient when your application talks directly to MySQL.

MySQLClient uses the mysql2 connector under the hood and accepts all the existing constructor options.

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Setup

import { MySQLClient } from '@linked-db/linked-ql/mysql';

const db = new MySQLClient({
  host: 'localhost',
  port: 3306,
  user: 'root',
  password: 'password',
  database: 'mydb',
  poolMode: false,
});

await db.connect();

const result = await db.query('SELECT 1 AS `result`');
console.log(result.rows);
// [{ result: 1 }]

await db.disconnect();

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Connection Mode

By default, MySQLClient runs on a single PostgreSQL connection.

You can opt into connection pooling by enabling poolMode:

const db = new MySQLClient({
  host: 'localhost',
  port: 3306,
  user: 'root',
  password: 'password',
  database: 'mydb',
  poolMode: true,
});

In poolMode, MySQLClient uses a connection pool to handle concurrent queries more efficiently.

After initializing the instance via db.connect(), subsequent db.connect() calls simply return a checked-out client.

This lets you explicitly check out a connection for session-sensitive work:

const client = await db.connect();
// ... run session-bound queries
client.release();

This is useful for transactions or workflows that require a stable connection.

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Realtime Setup

LinkedQL is designed to integrate with MySQL's binary log (binlog) for realtime capabilities.

To make this possible, binary logging must be enabled on the MySQL server.

At minimum, set in your database config file:

log_bin = ON

For correct change capture, row-based logging is recommended:

binlog_format = ROW

Refer to the official MySQL documentation for enabling and configuring binary logging.

Once binary logging is available, LinkedQL can build on top of it for realtime features.

NOTE

Realtime capabilities, specifically live queries and commit stream subscriptions, are not yet available on MySQL. Support for these features is planned and will build on the binlog-based foundation.

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Additional Reading

If you want to learn about...	Go to...
the common application-facing methods	API
how this fits into larger app architectures	Integration Patterns