Building Your First App: An

Introduction to MongoDB

Robert StamSoftware Engineer

MongoDB, Inc.

Great Wide Open Conference

Atlanta, April 2, 2014

What is MongoDB?

3

• Document

• Open source

• High performance

• Horizontally scalable

• Full featured

MongoDB is a __________ database

4

• Not for .PDF & .DOC files

• A document is essentially an associative array

• Document == JSON object

• Document == PHP Array

• Document == Python Dict

• Document == Ruby Hash

• Document == C# BsonDocument object model

• etc

Document Database

5

• MongoDB is an open source project

• On GitHub

• Licensed under the AGPL

• Started & sponsored by MongoDB, Inc

• Commercial licenses available

• Contributions welcome

Open Source

Database Landscape

7

• Written in C++

• Runs nearly everywhere

• Extensive use of memory-mapped files

i.e. read-through write-through memory caching.

• Data serialized as BSON (fast parsing)

• Full support for primary & secondary indexes

• Document model = less work

High Performance

8

• Ad Hoc queries

• Rich query capabilities

• Geospatial features

• Real time aggregation

• Eventually consistent

• Support for many programming languages

• Flexible schema

Full Featured

9

Indexing @

10

Replication @

11

Sharding @

mongodb.org/downloads

Document Database

RDBMS MongoDB

Table, View Collection

Row Document

Index Index

Join Embedded Document

Foreign Key Reference

Partition Shard

Terminology

Typical (relational) ERD

MongoDB ERD

We will build a library management

application http://www.flickr.com/photos/somegeekintn/3484353131/

First step in any application

Determine your entities

19

• Library Patrons (users)

• Books (card catalog)

• Authors

• Publishers

Library Management Application

Entities

In a relational based app

We would start by doing schema

design

21

• Users

• Books

• Authors

• Publishers

MongoDB Collections

Working with MongoDB

No common programming language

so we are using the MongoDB shell

24

> var user = {

username : "fred.jones",

first_name : "fred",

last_name : "jones"

}

Start with an Object(or array, hash, dict, etc)

25

> use library

> db.users.insert(user)

Insert the Record

No database or collection creation needed

26

> db.users.findOne()

{

_id : ObjectId("50804d0bd94ccab2da652599"),

username : "fred.jones",

first_name : "fred",

last_name : "jones"

}

Querying for the user

27

• _id is the primary key in MongoDB

• Automatically created as an ObjectId if not

provided

• Any unique immutable value could be used

• Automatically indexed

_id

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• ObjectId is a special 12 byte value

• Guaranteed to be unique across your cluster

• ObjectId("50804d0bd94ccab2da652599")

ObjectId

Timestamp Machine Pid Increment

50804d0b d94cca b2da 652599

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> db.author.insert({

first_name : "j.r.r.",

last_name : "tolkien",

bio : "J.R.R. Tolkien (1892.1973), beloved

throughout the world as the creator of The Hobbit and

The Lord of the Rings, was a professor of Anglo-Saxon

at Oxford, a fellow of Pembroke College, and a fellow

of Merton College until his retirement in 1959. His

chief interest was the linguistic aspects of the early

English written tradition, but even as he studied

these classics he was creating a set of his own."

})

Creating an Author

30

> db.books.insert({

title : "fellowship of the ring, the",

author : ObjectID("507ffbb1d94ccab2da652597"),

language : "english",

genre : [ "fantasy", "adventure" ],

publication : {

name : "george allen & unwin",

location : "London",

date : ISODate("1954-07-21T00:00:00Z")

}

})

Creating a Book

31

> db.books.findOne(

{ language : "english" },

{ genre : 1 })

{

"_id" : ObjectID("50804391d94ccab2da652598"),

"genre" : [

"fantasy",

"adventure"

]

}

Multiple Values per Key

32

> db.books.findOne(

{ genre : "fantasy" },

{ title : 1 })

{

"_id" : ObjectID("50804391d94ccab2da652598"),

"title" : "fellowship of the ring, the"

}

Querying for key with

multiple values

33

> db.books.findOne({}, { publication : 1 })

{

"_id" : ObjectID("50804391d94ccab2da652598"),

"publication" : {

"name" : "george allen & unwin",

"location" : "London",

"date" : ISODate("1954-07-21T00:00:00Z")

}

}

Nested Values

34

> db.books.update(

{ _id : ObjectID("50804391d94ccab2da652598") },

{ $set : {

isbn : "0547928211",

pages : 432

}}

)

True agile development. Simply Change how you work with the

data and the database follows

Update Books

35

> db.books.findOne()

{

"_id" : ObjectId("50804391d94ccab2da652598"),

"author" : ObjectId("507ffbb1d94ccab2da652597"),

"genre" : [ "fantasy", "adventure" ],

"isbn" : "0547928211",

"language" : "english",

"pages" : 432,

"publication" : {

"name" : "george allen & unwin",

"location" : "London",

"date" : ISODate("1954-07-21T00:00:00Z")

},

"title" : "fellowship of the ring, the"

}

Update Books

36

> db.books.ensureIndex({ title : 1 })

> db.books.ensureIndex({ genre : 1 }) // multikey

> db.books.ensureIndex({ "publication.date" : 1 })

Creating Indexes

37

> db.books.findOne({ title : /^fell/ })

{

"_id" : ObjectId("50804391d94ccab2da652598"),

"author" : ObjectId("507ffbb1d94ccab2da652597"),

"genre" : [ "fantasy", "adventure" ],

"isbn" : "0395082544",

"language" : "english",

"pages" : 432,

"publication" : {

"name" : "george allen & unwin",

"location" : "London",

"date" : ISODate("1954-07-21T00:00:00Z")

},

"title" : "fellowship of the ring, the"

}

Querying with RegEx

38

> db.books.insert({

title : "two towers, the",

author : ObjectID("507ffbb1d94ccab2da652597"),

language : "english",

isbn : "034523510X",

genre : [ "fantasy", "adventure" ],

page : 447,

publication : {

name : "george allen & unwin",

location : "London",

date : ISODate("1954-11-11T00:00:00Z")

}

})

Adding a Few More Books

39

> db.books.find(

{ author : ObjectId("507ffbb1d94ccab2da652597") })

.sort({ "publication.date" : -1 })

.limit(1)

{

"_id" : ObjectId("5080d33ed94ccab2da65259d"),

"title" : "return of the king, the",

"author" : ObjectId("507ffbb1d94ccab2da652597"),

"language" : "english",

"isbn" : "0345248295",

"genre" : [ "fantasy", "adventure" ],

"pages" : 544,

"publication" : {

"name" : "george allen & unwin",

"location" : "London",

"date" : ISODate("1955-10-20T00:00:00Z")

}

}

Cursors

40

> var page_num = 3;

> var results_per_page = 10;

> var cursor = db.books.find()

.sort({ publication_date : -1 })

.skip((page_num – 1) * results_per_page)

.limit(results_per_page);

Paging

41

> var book = db.books.findOne(

{ title : "return of the king, the" })

> db.author.findOne({ _id : book.author })

{

"_id" : ObjectId("507ffbb1d94ccab2da652597"),

"first_name" : "j.r.r.",

"last_name" : "tolkien",

"bio" : "J.R.R. Tolkien (1892.1973), beloved throughout

the world as the creator of The Hobbit and The Lord of the

Rings, was a professor of Anglo-Saxon at Oxford, a fellow of

Pembroke College, and a fellow of Merton College until his

retirement in 1959. His chief interest was the linguistic

aspects of the early English written tradition, but even as

he studied these classics he was creating a set of his own."

}

Finding Author by Book

MongoDB Drivers

Real Applications are not built in

the shell

MongoDB has native bindings

for over 12 languages

47

• Official Support for 12 languages

• Community drivers for many more

• Drivers connect applications to mongo servers

• Drivers translate BSON into native types

• mongo shell is not a driver, but works like one in some ways

• Installed using typical means (npm, pecl, gem, pip, nuget)

MongoDB Drivers

48

docs.mongodb.org

49

Online Training at MongoDB University

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Software Engineer, MongoDB Inc.

Robert Stam

Thank You