Connecting to database in Node.js from routes - mysql

Question

I'm working on a express server and am having trouble accessing my database from a route file I have set up for users. When I attempt to make a get request I receive this as an error.
"code": "ER_NO_DB_ERROR",
"errno": 1046,
"sqlState": "3D000",
"index": 0
I have been trying to look for a solution online but most of the answers suggest requiring db.js file everywhere which I already do. I have a feeling I need to pass the connection I made in app.js around but I am not sure how to do this. The relevant parts of my files are below. Database login info has been redacted, I do get a successful connection in app.js. I'm fairly new to this so any help would be appreciated, specifically if there is a better way to use the pool implemented in db.js.
app.js
var express = require('express');
var path = require('path');
var favicon = require('serve-favicon');
var logger = require('morgan');
var cookieParser = require('cookie-parser');
var bodyParser = require('body-parser');
var index = require('./routes/index');
var users = require('./routes/users');
var mysql = require('mysql')
var app = express();
var users = require('./routes/users');
var media = require('./routes/media');
var tv = require('./routes/tv');
var movies = require('./routes/movies');
var db = require('./db.js')
var connection = mysql.createConnection({
port: '3306',
host: '*********************',
user: '********',
password: '******'
})
db.connect(function(err) {
if (err) {
console.log('Unable to connect to MySQL.')
process.exit(1)
} else {
console.log('Successfully connected')
}
})
app.use('/api', users);
models/user.js
var db = require('../db.js');
var passwordHash = require('password-hash');
exports.getAll = function(done) {
db.get().query('SELECT * FROM users', function (err, rows) {
if (err) return done(err)
done(null, rows)
})
}
routes/users.js
var express = require('express');
var router = express.Router()
var user = require('../models/user');
var db = require('../db.js');
//this doesn't prInt anything currently. This is prompting me to believe I somehow
//need to pass a connection object or am using the pool properly.
console.log(db.get());
router.route('/users').get(function(req, res) {
user.getAll(function(err, users) {
if (err) {
return res.send(err);
}
res.json(users);
});
});
db.js
//this is taken mostly from a tutorial I found online
var mysql = require('mysql')
, async = require('async')
var PRODUCTION_DB = 'app_prod_database'
, TEST_DB = 'app_test_database'
exports.MODE_TEST = 'mode_test'
exports.MODE_PRODUCTION = 'mode_production'
var state = {
pool: null,
//mode: null,
}
exports.connect = function(done) {
state.pool = mysql.createPool({
port: '3306',
host: '***************',
user: '*********',
password: '*******'
//database: mode === exports.MODE_PRODUCTION ? PRODUCTION_DB : TEST_DB
})
//state.mode = mode
done()
}
exports.get = function() {
return state.pool
}
exports.fixtures = function(data) {
var pool = state.pool
if (!pool) return done(new Error('Missing database connection.'))
var names = Object.keys(data.tables)
async.each(names, function(name, cb) {
async.each(data.tables[name], function(row, cb) {
var keys = Object.keys(row)
, values = keys.map(function(key) { return "'" + row[key] + "'" })
pool.query('INSERT INTO ' + name + ' (' + keys.join(',') + ') VALUES (' + values.join(',') + ')', cb)
}, cb)
}, done)
}
exports.drop = function(tables, done) {
var pool = state.pool
if (!pool) return done(new Error('Missing database connection.'))
async.each(tables, function(name, cb) {
pool.query('DELETE * FROM ' + name, cb)
}, done)
}

Answer 1

Either supply a valid database in the createConnection...
var connection = mysql.createConnection({
port: '3306',
host: '*********************',
user: '********',
password: '******',
database: 'mydatabase'
And/or, qualify the table name with the name of the database in the query:
db.get().query('SELECT * FROM mydatabase.users',
^^^^^^^^^^^
What it looks like is happening in the current code, a connection is established to the MySQL Server. But no USE mydatabase statement has been executed. When the SQL statement SELECT ... FROM users is executed, MySQL doesn't know which database the users is supposed to reference. (That table could exist in multiple databases containing a table or view named users.)
That's what's causing the 1046 No database selected error.