data is not insert in mongodb - node.js

Question

I am beginner of nodejs and mongodb. I am inserting data to collection using mongoose ORM and model but not insert. Validation is working correct but data is not insert after filling complete data. I have not create collection in database manually. should I create collection manually in mongodb or create automatically when inserting document.
productsController
var mongoose = require('mongoose');
var db = require('../config/db_config');
var Product = require('../models/product');
//var Product = mongoose.model('Products');
var productController = {};
productController.add = function(req, res) {
var params = req.body;
if(!params) {
res.status(400).send({message: "Data can not be empty"});
}
var productData = new Product({
product_name : params.product_name,
price : params.price,
category : params.category
});
console.log(productData);
productData.save(function(err, product) {
if (err){
res.status(400).send({message:'Unable to save data! ' + err});
}else{
res.status(200).send({message:'Data has been saved! ' + product });
}
});
};
module.exports = productController;
Models code is here
var mongoose = require('mongoose');
var db = require('../config/db_config');
var Schema = mongoose.Schema;
var productSchema = new Schema({
product_name: { type: String, required: 'Product name cannot be left blank.' },
price: { type: String, required: 'Product price cannot be left blank.'},
category: { type: String , required: 'Product category cannot be left blank'},
updated_at : {type: Date, default: Date.now}
});
module.exports = mongoose.model('Products', productSchema);
routes file code is here:
var express = require('express');
var router = express.Router();
var mongoose = require('mongoose');
var Product = require('../models/product.js');
var productsController = require('../controllers/productsController');
router.post('/add',productsController.add);
module.exports = router;
DB config file
var mongoose = require('mongoose');
mongoose.Promise = global.Promise;
var db = mongoose.createConnection('mongodb://localhost:27017/nodeweb', function(err,db){
if(err){
throw err;
console.log(err);
} else {
console.log('Successfully connected to database!');
}
});
module.exports = db;
I have insert controller, model and routes file code.

Answer 1

Please correct your method -
Controller function
exports.add = function(req, res) {
var new_product = new Products(req.body);
// you have define Products not Product
console.log(new_product);
new_product.save(function(err, product) {
console.log('add data');
if (err){
res.send(err);
}else{
res.json(product);
}
});
};
and for good practice in node js - i think you can start with express-app-generator
This Helps to make simple routing, with generic responses and in-built express middlewares with loggers.

Answer 2

I have resolved problem. database connection work with connect method.
mongoose.connect('mongodb://localhost:27017/nodeweb', {useMongoClient: true}, function(err,db){
if(err){
throw err;
console.log(err);
} else {
console.log('Successfully connected to database!');
}
});