Node-IL Meetup 12/2

Getting Started With
MongoDB and
Mongoose
{ author: “Ynon Perek” }

Tuesday, February 12, 13

Whoami

Ynon Perek

http://ynonperek.com

ynon@ynonperek.com


Agenda

Mongo Is Awesome

CRUD Operations

Mongoose

Coding Time


COUC H DB CASSANDRA

Part of the NoSQL Family

SIMPLEDB
REDIS

FLOCKD
B


But Most Popular Of All


Mongo Is Awesome

Data Store for
JSON Objects


Mongo Is Awesome

Data Store for
JSON Objects

{
“Name” : “Rose Tyler”
}


JSON Objects

A JSON Object is a
collection of key/
value pairs {
"name" : "Rose Tyler",
Keys are simple "race" : "Human",
strings "body parts" : [ "head", "legs"]
}
Values can be:
Numbers, Strings,
Arrays, Other
Objects, and more


Mongo saves the data
in a binary format
called BSON

Spec:
http://bsonspec.org/


It’s A Document Oriented Data
Store


It don’t do joins


It don’t do transactions


Keeping It Simple

Document Oriented

No Transactions

No Joins


What Can Mongo Do For You

Create and store objects

Arrange them in collections

Retrieve them later


Q&A


CRUD Operations
Create, Read, Update and Destroy Data


Mongo CRUD

Create is called insert

Read is called find

Update is called update

Destroy is called remove


Mongo CRUD

db.highscore.insert ({"name":"Tom", "score":94});

db.highscore.find ({"name" : "Tom" })

db.highscore.update ({"name" : "Tom"},
{"$inc" : { "score" : 1 } });

db.highscore.remove ({"name" : "Tom"});


Mongoose
MongoDB + Node.JS = Awesome


What’s That

An Object Relational Mapper for Node.JS

Handles gory details so you don’t have to

Fat Models


Agenda

Hello Mongoose

Schema and Data Types

Custom Validators

Querying Data

Mongoose Plugins


Online Resources

http://mongoosejs.com/

https://github.com/LearnBoost/mongoose

irc: #mongoosejs on freenode


Hello Mongoose

var mongoose = require('mongoose');
mongoose.connect('localhost', 'test');

var schema = mongoose.Schema({ name: String });
var Cat = mongoose.model('Cat', schema);

var kitty = new Cat({ name: 'Zildjian' });
kitty.save(function (err) {
if (err) // ...
console.log('meow');
});


Mongoose Objects

Schema Schema

Model Model Model


Mongoose Objects

var schema = mongoose.Schema(
{ name: String });
{ name: String}

var Cat = mongoose.model(
'Cat', schema); Cat

var kitty = new Cat(
{ name: 'Zildjian' }); kitty


Demo

Express + Node.JS +
Mongoose

Contact List App


Schema Definitions

new Schema({
title: String,
A schema takes a
body: String,
description object
date: Date,
which specifies its keys
hidden: Boolean,
and their types meta: {
votes: Number,
Types are mostly favs: Number
normal JS }
});


Schema Types

String

Number

Date

Buffer

Boolean

Mixed

ObjectId

Array


Nested Objects

var PersonSchema = new Schema({
Creating nested objects name: {
first: String,
is easy
last: String
}
Just assign an object as });
the value


Array Fields

var PersonSchema = new Schema({
Array fields are easy name: {
first: String,
last: String
Just write the type as a },
single array element hobbies: [String]
});


Schema Use Case

Let’s start writing a
photo taking app var PhotoSchema = new Schema({
username: String,
Each photo is saved photo: String,
in the DB as a Data uploaded_at: Date
URL });

var Photo = mongoose.model(
Along with the
'Photo', PhotoSchema);
photo we’ll save the
username


Creating New Objects

Create a new object var mypic = new Photo({
by instantiating the username: 'ynon',
photo: 'data:image/
model gif;base64,R0lGOD
lhCwAOAMQfAP////7+',
Pass the values to uploaded_at: new Date()
the ctor });


Creating New Objects

After the object is
ready, simply save it
mypic.save();


What Schema Can Do For You

Add validations on var PhotoSchema = new Schema({
the fields username:
{ type: String, required: true },
Stock validators: photo:
required, min, max
uploaded_at: Date
Can also create });
custom validators

Validation happens
on save



Provide default var PhotoSchema = new Schema({
values for fields username:
Can use a photo:
function as { type: String, required: true },
default for uploaded_at:
{ type: Date, default: Date.now }
delayed
});
evaluation


Custom Validators

It’s possible to use your own validation code

var toySchema = new Schema({
color: String,
name: String
});

toySchema.path('color').validate(function(value) {
return ( this.color.length % 3 === 0 );
});


Schemas: Fat Models



Add methods to your documents

var EvilZombieSchema = new Schema({
name: String,
brainz: { type: Number, default: 0 }
});

EvilZombieSchema.methods.eat_brain = function() {
this.brainz += 1;
};


Schema Create Indices

A schema can have some fields marked as “index”. The
collection will be indexed by them automatically

var PhotoSchema = new Schema({
username: { type: String, required: true, index: true },
photo: { type: String, required: true },
uploaded_at: { type: Date, default: Date.now }
});


Schemas Create Accessors

A virtual field is not saved in the DB, but calculated from
existing fields. “full-name” is an example.

personSchema.virtual('name.full').get(function () {
return this.name.first + ' ' + this.name.last;
});

personSchema.virtual('name.full').set(function (name) {
var split = name.split(' ');
this.name.first = split[0];
this.name.last = split[1];
});


Querying Data

Use Model#find / Model#findOne to query data

// executes immediately, passing results to callback
MyModel.find({ name: 'john', age: { $gte: 18 }},
function (err, docs) {
// do something with data
// or handle err
});


Querying Data

You can also chain queries by not passing a callback

Pass the callback at the end using exec

var p = Photo.find({username: 'ynon'}).
skip(10).
limit(5).
exec(function(err, docs) {
console.dir( docs );
});


Other Query Methods

find( cond, [fields], [options], [cb] )

findOne ( cond, [fields], [options], [cb] )

findById ( id, [fields], [options], [cb] )

findOneAndUpdate( cond, [update], [options], [cb] )

findOneAndRemove( cond, [options], [cb] )


Counting Matches

Use count to discover how many matching documents
are in the DB

Adventure.count({ type: 'jungle' }, function (err, count) {
if (err) ..
console.log('there are %d jungle adventures', count);
});


Mongoose Plugins

A plugin connects to
the Schema and
extends it in a way


Mongoose Plugins

A mongoose plugin is a simple function which takes
schema and options

Demo: lastModifiedPlugin
https://gist.github.com/4657579


Mongoose Plugins

find or create plugin:

https://github.com/drudge/mongoose-findorcreate


Mongoose Plugins

Hashed password field plugin:
https://gist.github.com/4658951


Mongoose Plugins

Mongoose troops is a collection of useful mongoose
plugins:
https://github.com/tblobaum/mongoose-troop


Thanks For Listening

Ynon Perek

Slides at:
ynonperek.com

Talk to me at:
ynon@ynonperek.com


Node-IL Meetup 12/2

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