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JavaScript Build a REST API With Express Modeling Data for the API Connecting Mongoose to MongoDB

Brian Patterson
Brian Patterson
19,588 Points

Not sure why this hasn't saved

Not sure why this has not saved!

'use strict';

var mongoose = require('mongoose');


var db = mongoose.connection;

db.on('error', function(err) {
  console.error('connection error', err);

db.once('open', function() {
  console.log('db connection successful');
  //All database communication goes here.
  var Schema = mongoose.Schema;
  var AnimalSchema = new Schema({
    type: String,
    size: String,
    color: String,
    mass: Number,
    name: String
  var Animal = mongoose.model('Animal', AnimalSchema);
  var elephant = new Animal({
    type: 'elephant',
    size: 'big',
    color: 'gray',
    mass: 6000,
    name: 'Lawrence'

  elephant.save(function(err) {
    if (err) console.err('Save failed', err);
    else console.log('Saved');
    db.close(function() {
      console.log('db connection closed');
Adam Beer
Adam Beer
11,314 Points

Hi Brian! This is the good code. I don't understand what's happend. What does the console write? Maybe try to start the mongod, then in the next step type node mongoose_sandbox.js in an other cmd and finally mongo to connect to the server

1 Answer

Have you started Mongodb in a different console before trying to execute the code? I ran into this problem myself. I kept getting errors and the error message that it wasn't saving. The teacher didn't say to start the MongoDB or if they did I missed it...and I kept trying to figure out what was wrong. Turns out that was all it was. Easy to miss mistake in my case.