Project: The Local Library Website (Part Six)

Setting up the MongoDB database

Use MongoDB Atlas
Free cloud hosted sandbox database
Not for production, but great for development and prototyping it here.
Could also use Compose, ScaleGrid, ObjectRocket.
Create an account here: create an account
Then build da cluster button
Select region, then create cluster
Collections, add my own data
Database name: local_library
Collection name: Collection0
Then overview, connect
Allow access from anywhere
Create a user (see below)
Connect your application

Install Mongoose

Now we can set up install and mongoose

npm install mongoose

Connect to MongoDb

In app.js, we put the following text in. Make sure to use the above database string.
This code creates the default connection to the database, and also binds to the error event (to print errors to the console)

//Set up mongoose connection
var mongoose = require('mongoose');
var mongoDB = 'insert_your_database_url_here';

mongoose.connect(mongoDB, { useNewUrlParser: true , useUnifiedTopology: true});
var db = mongoose.connection;
db.on('error', console.error.bind(console, 'MongoDB connection error:'));

Defining the LocalLibrary Schema

Need to create modules for each model
Create the folder for models, then add these folders:

/express-locallibrary-tutorial //the project root

/models

author.js

book.js

bookinstance.js

genre.js

Author Model

Let’s create the author schema
This defines author as having a String SchemeType for first and family names.
Also a date field for dates of birth and death
There is also a virtual for the AuthorSchema. It’s called URL that returns the URL required to ge ta particular instance of the model

var mongoose = require('mongoose');
var Schema = mongoose.Schema;
var AuthorSchema = new Schema(
  {
    first_name: {type: String, required: true, maxLength: 100},
    family_name: {type: String, required: true, maxLength: 100},
    date_of_birth: {type: Date},
    date_of_death: {type: Date},
  }
);

// Virtual for author's full name
AuthorSchema
.virtual('name')
.get(function () {
  return this.family_name + ', ' + this.first_name;
});

// Virtual for author's lifespan
AuthorSchema.virtual('lifespan').get(function() {
  var lifetime_string = '';
  if (this.date_of_birth) {
    lifetime_string = DateTime.fromJSDate(this.date_of_birth).toLocaleString(DateTime.DATE_MED);
  }
  lifetime_string += ' - ';
  if (this.date_of_death) {
    lifetime_string += DateTime.fromJSDate(this.date_of_death).toLocaleString(DateTime.DATE_MED)
  }
  return lifetime_string;
});

// Virtual for author's URL
AuthorSchema
.virtual('url')
.get(function () {
  return '/catalog/author/' + this._id;
});

//Export model
module.exports = mongoose.model('Author', AuthorSchema);

Book Model

Also create a book model
Similar to the author model
Main difference – created two references to other models – Author and Genre

var mongoose = require('mongoose');
var Schema = mongoose.Schema;
var BookSchema = new Schema(

  {
    title: {type: String, required: true},
    author: {type: Schema.Types.ObjectId, ref: 'Author', required: true},
    summary: {type: String, required: true},
    isbn: {type: String, required: true},
    genre: [{type: Schema.Types.ObjectId, ref: 'Genre'}]
  }
);

// Virtual for book's URL
BookSchema
.virtual('url')
.get(function () {
  return '/catalog/book/' + this._id;
});
//Export model
module.exports = mongoose.model('Book', BookSchema);

BookInstance Model

BookInstance represents a specific copy of a book that someone might borrow. Information about whether the copy is available, what date it is back, what imprint or version.

var mongoose = require('mongoose');

var Schema = mongoose.Schema;

var BookInstanceSchema = new Schema(

  {

    book: { type: Schema.Types.ObjectId, ref: 'Book', required: true }, //reference to the associated book

    imprint: {type: String, required: true},

    status: {type: String, required: true, enum: ['Available', 'Maintenance', 'Loaned', 'Reserved'], default: 'Maintenance'},

    due_back: {type: Date, default: Date.now}

  }

);

// Virtual for bookinstance's URL

BookInstanceSchema

.virtual('url')

.get(function () {

  return '/catalog/bookinstance/' + this._id;

});

//Export model

module.exports = mongoose.model('BookInstance', BookInstanceSchema);

Genre Model – Challenge

Now need to create genre model.
It needs to have a String SchemaType called name
Name should be required to have between 3 and 100 characters.
Needs a virtual, called URL,
Need to be able to export the model

var mongoose = require('mongoose');

var Schema = mongoose.Schema;

var GenreSchema = new Schema(

  {

   name: {type: String, required: true, minLength: 3, maxLength: 100};

  }

);

// Virtual for author's URL

GenreSchema

.virtual('url')

.get(function () {

  return '/catalog/genre/‘ + this._id;

});

//Export model

module.exports = mongoose.model(‘Genre’, GenreSchema);

Testing it out!

Sample data: populatedb.js

npm install async

node populatedb <<string>>