This talk will introduce the philosophy and features of the open source, NoSQL MongoDB. We’ll discuss the benefits of the document-based data model that MongoDB offers by walking through how one can build a simple app to store books. We’ll cover inserting, updating, and querying the database of books.

1. #MongoDBDays
Building your first app;
an introduction to MongoDB
Thomas Rückstieß
Technical Services Engineer, MongoDB

2. Notes to the Presenter
• Themes for this presentation:
•
First presentation in the conference. Keep it fun
•
User is likely brand new to MongoDB and comes
from traditional relational background
•
This is an introduction. Don't go deep.. Introduce
concepts and refer to later presentations that build
on these concepts.

3. What is MongoDB?

4. MongoDB is a ___________ database
• Document
• Open source
• High performance
• Horizontally scalable
• Full featured

5. Document Database
• Not for .PDF & .DOC files
• A document is essentially an associative array
with key/value pairs (possibly nested)
{
username : “thomas.r",
num_logins : 39,
last_login : ISODate("2013-10-08T16:46:21Z"),
permissions : ["read", "write", "list", "admin"],
company : {
name : "MongoDB, Inc."
location : "Sydney, Australia"
}
}

6. Open Source
• MongoDB is an open source project
• On GitHub
• Licensed under the AGPL
• Started & sponsored by 10gen (now MongoDB, Inc.)
• Commercial licenses available
• Contributions welcome

7. High Performance
• Written in C++
• Extensive use of memory-mapped files
i.e. read-through write-through memory caching.
• Runs nearly everywhere
• Data serialized as BSON (fast parsing)
• Full support for primary & secondary indexes
• Document model = less work

8. Horizontally Scalable
Shard 1
Shard 2
Shard 3
Horizontally Scalable
Shard N

9. Full Featured
• Ad Hoc queries
• Real time aggregation
• Rich query capabilities
• Strongly consistent
• Geospatial features
• Support for most programming languages
• Flexible schema

10. Scalability & Performance
Scalability & Performance
Database Landscape
Memcached
MongoDB
RDBMS
Depth of Functionality

11. mongodb.org/downloads

12. Running MongoDB
$ tar –z xvf mongodb-osx-x86_64-2.4.x.tgz
$ cd mongodb-osx-i386-2.4.4/bin
$ mkdir –p /data/db
$ ./mongod

13. Mongo Shell
$ mongo
MongoDB shell version: 2.4.4
connecting to: test
> db.test.insert( { text: 'Welcome to MongoDB’ } )
> db.test.find().pretty()
{
"_id" : ObjectId("51c34130fbd5d7261b4cdb55"),
"text" : "Welcome to MongoDB"
}

14. Document Database

15. Terminology
RDBMS
MongoDB
Table, View
➜
Collection
Row
➜
Document
Index
➜
Index
Join
➜
Embedded Document
Foreign Key
➜
Reference
Partition
➜
Shard

16. Let’s Build a Blog

17. First step in any application is
Determine your entities

18. Entities in our Blogging System
• Users
• Articles
• Comments
• Tags
• Categories ( ? )

19. In a relational database app
We would start by doing schema design

20. Typical (relational) ERD
Category
·Name
·URL
User
·Name
·Email address
Article
·Name
·Slug
·Publish date
·Text
Comment
·Comment
·Date
·Author
Tag
·Name
·URL

21. Relational schema design
• Large ERD Diagrams
• Complex “create table” statements
• ORMs to map tables to objects
• Tables just to join tables together
• Lots of revisions until we get it right

22. In a MongoDB based app
We start building our app
and let the schema evolve

23. MongoDB ERD
Article
User
·Name
·Email address
·Name
·Slug
·Publish date
·Text
·Author
Comment[]
·Comment
·Date
·Author
Tag[]
·Value
Category[]
·Value

24. Working With MongoDB

25. The Shell

26. Start with an object
(or array, hash, dict, etc)
> var user = {
username: ’thomas.r',
first_name: ’Thomas',
last_name: ’Rückstieß',
}

27. Insert the Record
> db
test
> use blog
switched to db blog
// syntax is “db.<collection>.<command>”
> db.users.insert( user )
No db/collection creation necessary

28. Retrieve the Record again
// get one document (don’t care which one)
> db.users.findOne()
{
"_id" : ObjectId("50804d0bd94ccab2da652599"),
"username" : ”thomas.r",
"first_name" : ”Thomas",
"last_name" : ”Rückstieß"
}

29. _id
• _id is the primary key in MongoDB
• Any unique immutable value could be used
• Automatically created as an ObjectId if not provided
• Automatically indexed

30. ObjectId
• ObjectId is a special 12 byte value
• Guaranteed to be unique across your cluster
• ObjectId("50804d0bd94ccab2da652599")
ts
mac pid
inc

31. Creating a Blog Article
> db.articles.insert( {
title: ‘Hello World’,
body: ‘This is my first blog post’,
date: new Date(‘2013-06-20’),
username: ‘thomas.r’,
tags: [‘adventure’, ‘mongodb’],
comments: [ ]
})

32. Finding the Article
> db.articles.find().pretty()
{
"_id" : ObjectId("51c3bafafbd5d7261b4cdb5a"),
"title" : "Hello World",
"body" : "This is my first blog post",
"date" : ISODate("2013-06-20T00:00:00Z"),
"username" : ”thomas.r",
"tags" : [
"adventure",
"mongodb"
],
"comments" : [ ]
}

33. Finding the Article
> db.articles.find(
{ _id : ObjectId("51c3bafafbd5d7261b4cdb5a") } )
.pretty()
{
"_id" : ObjectId("51c3bafafbd5d7261b4cdb5a"),
"title" : "Hello World",
"body" : "This is my first blog post",
"date" : ISODate("2013-06-20T00:00:00Z"),
"username" : ”thomas.r",
"tags" : [
"adventure",
"mongodb"
],
"comments" : [ ]
}

34. Querying An Array
> db.articles.find( { tags : 'adventure’ } ).pretty()
{
"_id" : ObjectId("51c3bcddfbd5d7261b4cdb5b"),
"title" : "Hello World",
"body" : "This is my first blog post",
"date" : ISODate("2013-06-20T00:00:00Z"),
"username" : ”thomas.r",
"tags" : [
"adventure",
"mongodb"
],
"comments" : [ ]
}

35. Using Update to Add a Comment
// the syntax is: “ update ( what, how ) “
> db.articles.update(
{ _id: ObjectId("51c3bcddfbd5d7261b4cdb5b”) },
{ "$push" : {
"comments" : {
"name" : "Steve Noname",
"comment" : "Awesome Post"
}
}
)

36. Article with Comment Embedded
> db.articles.find( { username: “thomas.r” } ).pretty()
{
"_id" : ObjectId("51c3bcddfbd5d7261b4cdb5b"),
"body" : "This is my first blog post",
"comments" : [
{
"name" : "Steve Noname",
"comment" : "Awesome Post"
}
],
"date" : ISODate("2013-06-20T00:00:00Z"),
"tags" : [
"adventure",
"mongodb"
],
"title" : "Hello World",
"username" : ”thomas.r"
}

37. Remove Comments / Articles
// remove comment with $pull
> var last_comment = {
"name" : "Steve Noname",
"comment" : "Awesome Post”
}
> db.articles.update(
{ _id: ObjectId("51c3bcddfbd5d7261b4cdb5b") },
{ $pull : { comments: last_comment } }
)
// remove article
> db.articles.remove(
{ _id: ObjectId("51c3bcddfbd5d7261b4cdb5b") }
)

38. MongoDB Drivers

39. Real applications are not
built in the shell

40. MongoDB has native
bindings for over 12
languages

44. MongoDB Drivers
• Official Support for 12 languages
• Community drivers for tons more
• Drivers connect 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)

45. Learn more about MongoDB

46. Manual: docs.mongodb.org

47. Online Training at MongoDB University

48. We've introduced a lot of
concepts here

49. Schema Design @ 11:00
Article
User
·Name
·Email address
·Name
·Slug
·Publish date
·Text
·Author
Comment[]
·Comment
·Date
·Author
Tag[]
·Value
Category[]
·Value

50. Replication @ 11:50
Client Application
Driver
Re
a
d
a
Re
d
Write
Secondary
Primary
Secondary

51. Sharding @ 14:00
www.etiennemansard.com

52. Indexing @ 15:50
7
1
2
5
6
16
9
12
18
21

53. #MongoDBDays
Questions ?
Thomas Rückstieß
thomas@mongodb.com
@tomonezero