This document provides an introduction to MongoDB, including what it is, its key features, and how to work with documents in the MongoDB shell. MongoDB is an open-source, document-based database that is horizontally scalable, high performance, and full featured. It uses documents similar to JSON objects which can have various data structures. The document shows how to insert, query, update, and index documents using the MongoDB shell. Examples demonstrate working with collections like users, books, and authors in a sample library application. Schemas are flexible and evolve with the application's needs.

1. Technical Support Engineer
thomas@10gen.com
Thomas Rückstieß
#MongoDBDays
Building your first app;
an introduction to
MongoDB

2. What is MongoDB

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

4. Document Database
• Not for .PDF & .DOC files
• A document is essentially an associative array
• Document == JSON object
• Document == PHPArray
• Document == Python Dictionary
• Document == Ruby Hash
• etc

5. Open Source
• MongoDB is an open source project
• On GitHub
• Licensed under the AGPL
• Commercial licenses available
• Started & sponsored by 10gen
• Contributions welcome

6. 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

7. Horizontally Scalable

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

9. Database Landscape

10. http://www.mongodb.org/download
s

11. Mongo Shell

12. Document Database

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

14. Typical (relational) ERD

15. MongoDB ERD

16. http://www.flickr.com/photos/somegeekintn/3484353131/
We will build a library
management application

17. First step in any application is
Determine your entities

18. Library Management Application
Entities
• Library Patrons (users)
• Books (catalog)
• Authors
• Publishers
• Categories ??

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

20. Relational schema design
• Large ERD Diagrams
• Complex create table statements
• ORMs to map tables to objects
• Tables just to join tables together
• For this simple app we'd have 5 tables and 5 join
tables
• Lots of revisions until we get it just right

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

22. MongoDB collections
• Users
• Books
• Authors
• Publishers

23. No common language
so using the shell

24. Working with MongoDB

25. user = {
username: 'fred.jones',
first_name: 'fred',
last_name: 'jones’
}
Start with an object
(or array, hash, dict, etc)

26. > db.users.insert(user)
Insert the record
No collection creation
needed

27. > db.users.findOne()
{
"_id" : ObjectId("50804d0bd94ccab2da652599"),
"username" : "fred.jones",
"first_name" : "fred",
"last_name" : "jones"
}
Querying for the user

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

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

30. > 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

31. > db.author.findOne( { last_name : 'tolkien' } )
{
"_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."
}
Querying for our author

32. > 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: new Date('21 July 1954'),
}
})
Creating a Book
http://society6.com/PastaSoup/The-Fellowship-of-the-Ring-ZZc_Print/

33. > db.books.findOne({language: 'english'}, {genre: 1})
{
"_id" : ObjectId("50804391d94ccab2da652598"),
"genre" : [
"fantasy",
"adventure"
]
}
Multiple values per key

34. > db.books.findOne({genre: 'fantasy'}, {title: 1})
{
"_id" : ObjectId("50804391d94ccab2da652598"),
"title" : "fellowship of the ring, the"
}
Querying for key with
multiple values
Query key with single value or
multiple values the same way.

35. > db.books.findOne({}, {publication: 1})
{
"_id" : ObjectId("50804ec7d94ccab2da65259a"),
"publication" : {
"name" : "george allen & unwin",
"location" : "London",
"date" : ISODate("1954-07-21T04:00:00Z")
}
}
Nested Values

36. > db.books.findOne(
{'publication.date' :
{ $lt : new Date('21 June 1960')}
}
)
{
"_id" : ObjectId("50804391d94ccab2da652598"),
"title" : "fellowship of the ring, the",
"author" : ObjectId("507ffbb1d94ccab2da652597"),
"language" : "english",
"genre" : [ "fantasy", "adventure" ],
"publication" : {
"name" : "george allen & unwin",
"location" : "London",
"date" : ISODate("1954-07-21T04:00:00Z")
}
}
Reach into nested values
using dot notation

37. > db.books.update(
{"_id" : ObjectId("50804391d94ccab2da652598")},
{ $set : {
isbn: '0547928211',
pages: 432
}
})
Update books
True agile development.
Simply change how you work with
the data and the database follows

38. db.books.findOne()
{
"_id" : ObjectId("50804ec7d94ccab2da65259a"),
"author" : ObjectId("507ffbb1d94ccab2da652597"),
"genre" : [ "fantasy", "adventure" ],
"isbn" : "0395082544",
"language" : "english",
"pages" : 432,
"publication" : {
"name" : "george allen & unwin",
"location" : "London",
"date" : ISODate("1954-07-21T04:00:00Z")
},
"title" : "fellowship of the ring, the"
}
The Updated Book record

39. > db.books.ensureIndex({title: 1})
> db.books.ensureIndex({genre : 1})
> db.books.ensureIndex({'publication.date': -1})
Creating indexes

40. > db.books.findOne({title : /^fell/})
{
"_id" : ObjectId("50804ec7d94ccab2da65259a"),
"author" : ObjectId("507ffbb1d94ccab2da652597"),
"genre" : [ "fantasy", "adventure" ],
"isbn" : "0395082544",
"language" : "english",
"pages" : 432,
"publication" : {
"name" : "george allen & unwin",
"location" : "London",
"date" : ISODate("1954-07-21T04:00:00Z")
},
"title" : "fellowship of the ring, the"
}
Querying with RegEx

41. > db.books.insert({
title: 'two towers, the',
author: ObjectId("507ffbb1d94ccab2da652597"),
language: 'english',
isbn : "034523510X",
genre: ['fantasy', 'adventure'],
pages: 447,
publication: {
name: 'george allen & unwin',
location: 'London',
date: new Date('11 Nov 1954'),
}
})
Adding a few more books
http://society6.com/PastaSoup/The-Two-Towers-XTr_Print/

42. > db.books.insert({
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: new Date('20 Oct 1955'),
}
})
Adding a few more books
http://society6.com/PastaSoup/The-Return-of-the-King-Jsc_Print/

43. > 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("1955-10-20T04:00:00Z")
}
}
Cursors

44. page_num = 3; results_per_page = 10; cursor =
db.books.find() .sort({ "publication.date" : -1 })
.skip((page_num - 1) * results_per_page)
.limit(results_per_page);
Paging

45. > 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

46. MongoDB Drivers

47. Real applications are not
built in the shell

48. MongoDB has native
bindings for over 12
languages

51. 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)

52. Next Steps

53. We've introduced a lot of
concepts here

54. Schema Design @ 10:35 am

55. Replication @ 11:30 am

56. Sharding @ 12:15 pm

57. Indexing @ 14:30 pm

58. Technical Support Engineer
thomas@10gen.com
Thomas Rückstieß
#MongoDBDays
Questions?
Fragen?
• Schema Design @ 10:35
• Replication @ 11:30
• Sharding @ 12:15
• Indexing @ 14:30