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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.