Q. Mongoose

MongoDB object modeling for node.js

Mongoose provides a straight-forward, schema-based solution to model your application data. It includes built-in type casting, validation, query building, business logic hooks and more, out of the box.

Mongoose Guide

Q. Defining your schema

Everything in Mongoose starts with a Schema. Each schema maps to a MongoDB collection and defines the shape of the documents within that collection.

var kittySchema = mongoose.Schema({

name: String,

gender: String,

birth: Date,

age: Number,

hidden: Boolean

});

Schemas not only define the structure of your document and casting of properties, they also define document

instance methods, static Model methods, compound indexes and document lifecycle hooks called middleware

Q. The Permitted Schema Types

• String
• Number
• Date
• Buffer
• Boolean
• Mixed
• ObjectId
• Array

Ref: Mongoose Schema Types

Q. Instance methods

Instances of Models are documents. Documents have many of their own built-in instance methods. We may also define our own custom document instance methods too.

Note: methods must be added to the schema before compiling it with mongoose.model()

kittySchema.methods.speak = function () {

var greeting = this.name

? "Meow name is " + this.name

: "I don't have a name";

console.log(greeting);

}

Q. Static model methods, Query Helpers, Indexes, Virtuals

<TODO ...>

Q. Creating a model

To use our shcema definition, we need to convert our kittySchemainto a Model we can work with.

To do so, we pass it into mongoose.model(modelName, schema);

Creating a model called Kitten

var Kitten = mongoose.model('Kitten', kittySchema);

Creating Kitten instances (documents)

var silence = new Kitten({ name: 'Silence' });

var fluffy = new Kitten({ name: 'fluffy' });

console.log(silence.name); // 'Silence'

All of our Kitten instances have a speak() method available to it.

fluffy.speak(); // "Meow name is fluffy"

Q. Operations

Each document can be saved to the database by calling its save method

fluffy.save(function (err, fluffy) {

if (err) return console.error(err);

fluffy.speak();

});

Mongoose supports MongoDBs rich querying syntax.

Kitten.findOne({ name: /^fluf/ }, function(err, akitten) {

if (err) return handleError(err);

console.log('Kitten [ %s ] has found in DB', akitten.name)

});

Q. Misc

If the Node process ends, close the Mongoose connection

process.on('SIGINT', function() {

mongoose.connection.close(function () {

console.log('Mongoose disconnected on app termination');

process.exit(0);

});

});