This document provides an overview of MongoDB including what it is, how to use it, best practices for database design, building scalable applications, and new transaction capabilities in MongoDB 4.0. It defines MongoDB as a non-relational database that uses documents with dynamic schemas, nested objects and arrays. It covers CRUD operations, queries, indexing, aggregation, denormalization techniques, replica sets, sharding, choosing the right shard key, and how to implement transactions in MongoDB 4.0 including starting a session, transaction, and committing or rolling back changes.

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Neha Nivedita
Getting Ahead With MongoDB

2. Development | Consulting | Training

3. PARTNERS, ALLIANCES & OFFICES
33
INDIA
AUSTRALIA
USA
NORWAY
S. AFRICA
SINGAPORE

4. ABOUT ME
44
Open Source Contribution
Node.js
React
Enzyme
Meteor
Full Stack Developer
JavaScript
Node.js
React
MongoDB
MEAN
Speaker
JS Fusion
Meteor Noida
DeveloperWeek
MongoDB World
MongoDB Certified
Developer
Trainer

5. Points of Discussion
55
What’s MongoDB
How to use it
Effective DB Design Nexus Architecture
Building scalable apps Bonus Section!

6. What is MongoDB?

7. Some Popular Databases
7
WHAT IS MONGODB?
7
Oracle
MySQL
MSSQL
PostgreSQL
MongoDB

8. Architecture
8
WHAT IS MONGODB?
8

9. MongoDB Document
{
name : “Black Panther”,
title : “King”,
address : {
address1: “Throne Room”,
address2: “Royal Palace”,
country : “Wakanda”,
}
associates: [ “Shuri”, “Okoye”, “Nakia”, “Ramonda”],
punches_dropped : 1734879,
}
key value
string
nested document
or object
array
integer
WHAT IS MONGODB?

10. Why use MongoDB?
10
WHAT IS MONGODB?
10
Schemaless
JavaScript
everywhere!
Fast IO
Horizontal
scaling

11. Vertical Scaling
11
WHAT IS MONGODB?
11

12. Horizontal Scaling
12
WHAT IS MONGODB?
12

13. RECAP
13
WHAT IS MONGODB?
13
Documents, collections & database
Benefits of MongoDB
Scalability

14. How to use MongoDB

15. MongoDB Query Language
15
HOW TO USE MONGODB?
15
Query syntax:
db.<collection>.<operation>({ <key>: <value> });

16. CRUD Operations
16
HOW TO USE MONGODB?
16
Create:
db.avengers.insert({ name: ‘thor’ });
{
_id: 1,
name: ‘thor’
}
avengers

17. CRUD Operations
17
HOW TO USE MONGODB?
17
Read:
db.avengers.find({ name: ‘thor’ });
{
_id: 1,
name: ‘thor’
}
avengers
[{
_id: 1,
name: ‘thor’
}]
Result set:

18. CRUD Operations
18
HOW TO USE MONGODB?
18
Update:
db.avengers.update({ name: ‘thor’ }, { brother: ‘loki’ });
{
_id: 1,
name: ‘thor’,
brother: ‘loki’
}
avengers
{
_id: 1,
name: ‘thor’
}
avengers

19. CRUD Operations
19
HOW TO USE MONGODB?
19
Delete:
db.avengers.remove({ name: ‘thor’ });
avengers
{
_id: 1,
name: ‘thor’,
brother: ‘loki’
}
avengers

20. Cursor Operations
20
HOW TO USE MONGODB?
20
Count: db.avengers.find({ team: ‘Iron Man’ }).count();
Sort: db.avengers.find({ team: ‘Iron Man’ }).sort({ name: -1 });
Skip: db.avengers.find({ team: ‘Iron Man’ }).skip(5);
Limit: db.avengers.find({ team: ‘Iron Man’ }).limit(10);

21. Aggregation
21
HOW TO USE MONGODB?
21
{ _id: 1, name: ‘Captain America’, location: “Earth”, punches: 1273453, team: “Cap” },
{ _id: 2, name: ‘Iron Man’, location: “Earth”, punches: 798712, team: “Iron Man” },
{ _id: 3, name: ‘The Vision’, location: “Earth”, punches: 3465, team: “Iron Man” },
{ _id: 4, name: ‘Bucky’, location: “Earth”, punches: 9732, team: “Cap” },
{ _id: 5, name: ‘Black Widow’, location: “Earth”, punches: 923213, team: “Iron Man” },
{ _id: 6, name: ‘Hawkeye’, location: “Earth”, punches: 8745, team: “Cap” },
{ _id: 7, name: ‘Thor’, location: “Asgard”, punches: 8721345, team: “None” },
{ _id: 8, name: ‘Hulk’, location: “Nobody knows”, punches: 4097392, team: “Hulk” },
collection: avengers

22. Aggregation
22
HOW TO USE MONGODB?
22
db.avengers.aggregate([
{ $match: { location: "Earth" } },
{ $group: {
_id: "$team",
total_punches: { $sum: "$punches" }
}
},
{ $sort: { total_punches: -1 } }
]);
Pipeline stages: $match -> $group -> $sort
[
{
_id: ‘Iron Man’,
total_punches: 1725390
},
{
_id: ‘Cap’,
total_punches: 1291930
}
]
Result set:

23. RECAP
23
HOW TO USE MONGODB?
23
CRUD operations
Cursor operations
Aggregation

24. Effective DB Design

25. Thought Transformation
25
EFFECTIVE DB DESIGN
25
Degree of
association
Relational
or not?
Understand your
data & think
differently
Is NoSQL right
for your use
case?
How deeply
relational is your
data?
01 02 03 To what extent
each document can
be denormalized?
How many relations
exist per
document?

26. Denormalize properly
26
EFFECTIVE DB DESIGN
26
shows
castMembers
reviews
episodes
seasons
many
many
many
many

27. What not to do
27
EFFECTIVE DB DESIGN
27
{
title: 'Agents of SHIELD',
seasons: [
{
seasonNumber: 1,
episodes: [
{
episodeNumber: 1,
title: 'Pilot',
castMembers: [{ name: 'Chloe Bennet', ... }, {...}],
reviews: [{ author: ‘Stan Lee’, stars: 4, ... }, {...}],
}
]
}
]
}

28. Understand your data
28
EFFECTIVE DB DESIGN
28
Degree of relation
Embedded documents
References

29. One to One
29
MODELLING
29

30. One to Few
30
MODELLING
30

31. One to Many
31
MODELLING
31

32. One to Squillions
32
MODELLING
32

33. Use Indexes Correctly
33
EFFECTIVE DB DESIGN
33
Covered queries
Compound indexes
Sorting with indexes
Use query analysis: .explain()

34. RECAP
34
EFFECTIVE DB DESIGN
34
Model data correctly!
Contemplate the N in one-to-N!
Keep your queries covered!

35. Building Scalable Apps

36. Building scalable apps
36
BUILDING SCALABLE APPS
36
Choosing
Shard Key
Sharding
Replication
When to
Shard Scale easy!

37. Replica Set
37
BUILDING SCALABLE APPS
37

38. Replica Set
38
BUILDING SCALABLE APPS
38

39. Replica Set
39
BUILDING SCALABLE APPS
39

40. Shards
40
BUILDING SCALABLE APPS
40

41. Shards
41
BUILDING SCALABLE APPS
41

42. Shards
42
BUILDING SCALABLE APPS
42

43. Shards
43
BUILDING SCALABLE APPS
43

44. Choosing a Shard Key
44
BUILDING SCALABLE APPS
44
Shard Key determines how your data is divided
Create a Shard Key that targets a single shard
High degree of randomness
Easily divisible shards

45. When to Shard
45
BUILDING SCALABLE APPS
45
Plan ahead
Choose a shard key wisely - it cannot be changed
You cannot unshard a sharded collection

46. RECAP
46
BUILDING SCALABLE APPS
46
Use replicas for high availability
Shard your data for high scalability
Choose shard keys correctly!

47. Nexus Architecture

48. Nexus Architecture
48
ARCHITECTURE
48

49. Transactions (in 4.0!)

50. Transactions in 4.0
50
TRANSACTIONS
50
Beta documentation is out
Similar to SQL transactions
Has some limitations

51. Transactions in 4.0
51
TRANSACTIONS
51
Start client session:
client_session = client.start_session()

52. Transactions in 4.0
52
TRANSACTIONS
52
Start transaction:
client_session.start_transaction()

53. Transactions in 4.0
53
TRANSACTIONS
53
Pass the session to each transaction operation:
db.collection.insert_one({... }, session=client_session)
db.collection.insert_one({...}, session=client_session)
[...]
db.collection.update_many({...}, {...}, session=client_session)
my_doc = db.collection.find_one({...}, session=client_session)

54. Transactions in 4.0
54
TRANSACTIONS
54
Commit or rollback to end the transaction:
client_session.commit_transaction()
OR
client_session.abort_transaction()

55. Transactions in 4.0
55
TRANSACTIONS
55
Runtime limit < 1 min
Oplog size limit < 16 MB
Beta testing starts soon

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THANK YOU
Neha Nivedita @nodexperts
neha@nodexperts.com www.nodexperts.com