Skip to main content

How to handle errors?

This section details error handling techniques in MySQL2. It covers essential error management strategies for methods such as createConnection, createPool, createPoolCluster, execute and query.

Using callbacks​

createConnection
2Stable

This solution has been tested and confirmed as the correct answer.

Handling connection errors by adding an error event listener:

const mysql = require('mysql2');

connection = mysql.createConnection({
  host: '',
  user: '',
  database: '',
});

connection.addListener('error', (err) => {
  if (err instanceof Error) {
    console.log(`createConnection error:`, err);
  }
});
createPool
2Stable

This solution has been tested.

Handling connection errors through callback's err parameter:

const mysql = require('mysql2');

const pool = mysql.createPool({
  host: '',
  user: '',
  database: '',
});

pool.getConnection((err, connection) => {
  if (err instanceof Error) {
    console.log('pool.getConnection error:', err);
    return;
  }
});
createPoolCluster
2Stable

This solution has been tested.

Handling connection errors through callback's err parameter:

const mysql = require('mysql2');

const poolCluster = mysql.createPoolCluster();

poolCluster.add('NodeI', {
  host: '',
  user: '',
  database: '',
});

poolCluster.getConnection('NodeI', (err, connection) => {
  if (err instanceof Error) {
    console.log('poolCluster.getConnection error:', err);
    return;
  }
});
execute
2Stable

This solution has been tested.

Handling execute errors through callback's err parameter:

connection.execute('SELEC 1 + 1', (err, rows) => {
  if (err instanceof Error) {
    console.log('execute error:', err);
    return;
  }

  console.log(rows);
});
  • It will work for both createConnection, createPool and createPoolCluster connections.
query
2Stable

This solution has been tested.

Handling query errors through callback's err parameter:

connection.query('SELEC 1 + 1', (err, rows) => {
  if (err instanceof Error) {
    console.log('query error:', err);
    return;
  }

  console.log(rows);
});
  • It will work for both createConnection, createPool and createPoolCluster connections.

Using promises​

createConnection
2Stable

This solution has been tested and confirmed as the correct answer.

Handling connection errors through try-catch block:

import mysql from 'mysql2/promise';

try {
  const connection = await mysql.createConnection({
    host: '',
    user: '',
    database: '',
  });
} catch (err) {
  if (err instanceof Error) {
    console.log(err);
  }
}
createPool
2Stable

This solution has been tested.

Handling connection errors through try-catch block:

import mysql from 'mysql2/promise';

const pool = mysql.createPool({
  host: '',
  user: '',
  database: '',
});

try {
  const connection = await pool.getConnection();
} catch (err) {
  if (err instanceof Error) {
    console.log(err);
  }
}
createPoolCluster
2Stable

This solution has been tested.

Handling connection errors through try-catch block:

import mysql from 'mysql2/promise';

const poolCluster = mysql.createPoolCluster();

poolCluster.add('NodeI', {
  host: '',
  user: '',
  database: '',
});

try {
  await poolCluster.getConnection('NodeI');
} catch (err) {
  if (err instanceof Error) {
    console.log('createConnection error:', err);
  }
}
execute
2Stable

This solution has been tested.

Handling execute errors through try-catch block:

try {
  const [rows] = await connection.execute('SELEC 1 + 1');
  console.log(rows);
} catch (err) {
  if (err instanceof Error) {
    console.log('execute error:', err);
  }
}
  • It will work for both createConnection, createPool and createPoolCluster connections.
query
2Stable

This solution has been tested.

Handling query errors through try-catch block:

try {
  const [rows] = await connection.query('SELEC 1 + 1');
  console.log(rows);
} catch (err) {
  if (err instanceof Error) {
    console.log('query error:', err);
  }
}
  • It will work for both createConnection, createPool and createPoolCluster connections.