How do I integrate MYSQL with Sveltekit / nodejs

Question

Typically for a nodejs project I just follow this standard example:

var mysql      = require('mysql');
var connection = mysql.createConnection({
  host     : 'localhost',
  user     : 'me',
  password : 'secret',
  database : 'my_db'
});
 
connection.connect();
 
connection.query('SELECT 1 + 1 AS solution', function (error, results, fields) {
  if (error) throw error;
  console.log('The solution is: ', results[0].solution);
});
 
connection.end();

Sveltekit doesn't allow the var mysql = require('mysql'); So I tried replacing that with import { mysql } from 'mysql'; Which also doesn't work. Not sure if anyone has experience with this and can direct me to understand my mistake.

Answer 1

1. Install mysql2 package

npm install --save mysql2

2. Setup MySQL connection

lib/db/mysql.js

import mysql from 'mysql2/promise';

export const mysqlconn = await mysql.createConnection({ 
    host: '<myhost>',
    user: 'root',
    password: 'mypassword',
    database: 'mydatabase'
});

3. Create an API endpoint

routes/api/read.js

import { mysqlconn } from '$lib/db/mysql';


export async function get() {
    
    let results = await mysqlconn.query('SELECT * FROM mytable')
        .then(function([rows,fields]) {
            console.log(rows);
            return rows;
        });
    
    return {
        body: results
    }
}

---

UPDATE

Which is better? The above code or this code?

1. Install mysql2 package

npm install --save mysql2

2. Setup MySQL connection

lib/db/mysql.js

import mysql from 'mysql2/promise';

let mysqlconn = null;

export function mysqlconnFn() {

    if (!mysqlconn) {
        mysqlconn = mysql.createConnection({ 
            host: '<myhost>',
            user: 'root',
            password: 'mypassword',
            database: 'mydatabase'
        });
    }

    return mysqlconn;
}

3. Create an API endpoint

routes/api/read.js

import { mysqlconnFn } from '$lib/db/mysql';


export async function get() {

    let mysqlconn = await mysqlconnFn();

    let results = await mysqlconn.query('SELECT * FROM mytable')
        .then(function([rows,fields]) {
            console.log(rows);
            return rows;
        });
    
    return {
        body: results
    }
}

---

Update 2

You can also set up MySQL connection in hooks.

Refer: https://github.com/sveltejs/kit/issues/1538#issuecomment-1002106271

Answer 2

may something like knex works?

// in /src/lib/db.js
import knex from 'knex'

export default knex({
  client: 'mysql',
  version: '5.7',
  connection: {
    host: '127.0.0.1',
    port: 3306,
    user: 'root',
    password: '',
    database: 'library'
  },
})

anywhere in endpoint

// in /src/routes/api/books.js
import db from '$lib/db'

// get all books
export const get = async request => {
  const books= await db.select().from('books')

  if (voters) {
    return {
      body: {
        books
      }
    }
  }
  // else
}

// add a book
export const post = async ({ body }) => {
  const added = await db
    .insert({
      title: body.get('title'),
      author: body.get('author'),
    // .insert(JSON.parse(body)) // or you can send JSON.stringfy(dataObject)
    .into('admins')

  if (added) {
    return {
      status: 200,
      body: {
        message: 'A book added successfully'
      }
    }
  }
  // else
}

you can fetch it the way you like,,

this is may not appropriate answer, i just found it last weekend

• about knex : https://knexjs.org/
• about endpoint : https://kit.svelte.dev/docs#routing-endpoints