The document discusses the transition from SQL to NoSQL, specifically MongoDB, highlighting the need to map SQL terms to MongoDB concepts, understanding the advantages of using MongoDB, and changing one's mindset regarding data modeling. It emphasizes document-based data storage, schema flexibility, and faster data retrieval without expensive joins. The author, Lauren Schaefer, provides examples to illustrate the differences in data modeling and querying between SQL and MongoDB.

2. From SQL to NoSQL—
Changing Your Mindset
@Lauren_Schaefer, Developer Advocate,
MongoDB

3. Parks and Recreation, Season 6, Episode 14

7. Parks and Recreation, Season 6, Episode 14

8. Lauren Schaefer
Developer Advocate, MongoDB
@Lauren_Schaefer

9. From SQL to NoSQL—
Changing Your Mindset

10. Make the leap from SQL to
MongoDB1. Map terms & concepts from SQL to MongoDB
2. Discover the 4 humongous advantages of MongoDB
3. Change your mindset in 3 key ways

11. Make the leap from SQL to
MongoDB1. Map terms & concepts from SQL to MongoDB
2. Discover the 4 humongous advantages of MongoDB
3. Change your mindset in 3 key ways

12. MongoDB stores data in documents

13. MongoDB stores data in documents
{
first_name: "Paul",
surname: "Miller",
cell: "447557505611",
city: "London",
location: [45.123,47.232],
profession: ["banking", "finance", "trader"],
cars: [
{
model: "Bentley",
year: 1973
},
{
model: "Rolls Royce",
year: 1965
}
]
}
#MDBlocal @Lauren_Schaef

14. MongoDB stores data in documents
{
first_name: "Paul",
surname: "Miller",
cell: "447557505611",
city: "London",
location: [45.123,47.232],
profession: ["banking", "finance", "trader"],
cars: [
{
model: "Bentley",
year: 1973
},
{
model: "Rolls Royce",
year: 1965
}
]
}
#MDBlocal @Lauren_Schaef

15. MongoDB stores data in documents
{
first_name: "Paul",
surname: "Miller",
cell: "447557505611",
city: "London",
location: [45.123,47.232],
profession: ["banking", "finance", "trader"],
cars: [
{
model: "Bentley",
year: 1973
},
{
model: "Rolls Royce",
year: 1965
}
]
}
#MDBlocal @Lauren_Schaef

16. MongoDB stores data in documents
{
first_name: "Paul",
surname: "Miller",
cell: "447557505611",
city: "London",
location: [45.123,47.232],
profession: ["banking", "finance", "trader"],
cars: [
{
model: "Bentley",
year: 1973
},
{
model: "Rolls Royce",
year: 1965
}
]
}
#MDBlocal @Lauren_Schaef

17. MongoDB stores data in documents
{
first_name: "Paul",
surname: "Miller",
cell: "447557505611",
city: "London",
location: [45.123,47.232],
profession: ["banking", "finance", "trader"],
cars: [
{
model: "Bentley",
year: 1973
},
{
model: "Rolls Royce",
year: 1965
}
]
}
#MDBlocal @Lauren_Schaef

18. MongoDB stores data in documents
{
first_name: "Paul",
surname: "Miller",
cell: "447557505611",
city: "London",
location: [45.123,47.232],
profession: ["banking", "finance", "trader"],
cars: [
{
model: "Bentley",
year: 1973
},
{
model: "Rolls Royce",
year: 1965
}
]
}
#MDBlocal @Lauren_Schaef

19. MongoDB stores data in documents
{
first_name: "Paul",
surname: "Miller",
cell: "447557505611",
city: "London",
location: [45.123,47.232],
profession: ["banking", "finance", "trader"],
cars: [
{
model: "Bentley",
year: 1973
},
{
model: "Rolls Royce",
year: 1965
}
]
}
#MDBlocal @Lauren_Schaef

20. MongoDB stores data in documents
{
first_name: "Paul",
surname: "Miller",
cell: "447557505611",
city: "London",
location: [45.123,47.232],
profession: ["banking", "finance", "trader"],
cars: [
{
model: "Bentley",
year: 1973
},
{
model: "Rolls Royce",
year: 1965
}
]
}
#MDBlocal @Lauren_Schaef

21. Modeling data in MongoDB vs
SQL
{
first_name: "Paul",
surname: "Miller",
cell: "447557505611",
city: "London",
location: [45.123,47.232],
profession: ["banking", "finance", "trader"],
cars: [
{
model: "Bentley",
year: 1973
},
{
model: "Rolls Royce",
year: 1965
}
]
}
#MDBlocal @Lauren_Schaef

22. Modeling data in MongoDB vs
SQL
{
first_name: "Paul",
surname: "Miller",
cell: "447557505611",
city: "London",
location: [45.123,47.232],
profession: ["banking", "finance", "trader"],
cars: [
{
model: "Bentley",
year: 1973
},
{
model: "Rolls Royce",
year: 1965
}
]
}
ID first_name surname cell city location_x location_y
1 Paul Miller 447557505611 London 45.123 47.232
Users
#MDBlocal @Lauren_Schaef

23. Modeling data in MongoDB vs
SQL
{
first_name: "Paul",
surname: "Miller",
cell: "447557505611",
city: "London",
location: [45.123,47.232],
profession: ["banking", "finance", "trader"],
cars: [
{
model: "Bentley",
year: 1973
},
{
model: "Rolls Royce",
year: 1965
}
]
}
ID first_name surname cell city location_x location_y
1 Paul Miller 447557505611 London 45.123 47.232
Users
ID user_id profession
10 1 banking
11 1 finance
12 1 trader
Professions
#MDBlocal @Lauren_Schaef

24. Modeling data in MongoDB vs
SQL
{
first_name: "Paul",
surname: "Miller",
cell: "447557505611",
city: "London",
location: [45.123,47.232],
profession: ["banking", "finance", "trader"],
cars: [
{
model: "Bentley",
year: 1973
},
{
model: "Rolls Royce",
year: 1965
}
]
}
ID user_id profession
10 1 banking
11 1 finance
12 1 trader
Professions
ID user_id model year
20 1 Bentley 1973
21 1 Rolls Royce 1965
Cars
ID first_name surname cell city location_x location_y
1 Paul Miller 447557505611 London 45.123 47.232
Users
#MDBlocal @Lauren_Schaef

25. Modeling data in MongoDB vs
SQL
{
first_name: "Paul",
surname: "Miller",
cell: "447557505611",
city: "London",
location: [45.123,47.232],
profession: ["banking", "finance", "trader"],
cars: [
{
model: "Bentley",
year: 1973
},
{
model: "Rolls Royce",
year: 1965
}
]
}
ID user_id profession
10 1 banking
11 1 finance
12 1 trader
Professions
ID user_id model year
20 1 Bentley 1973
21 1 Rolls Royce 1965
Cars
ID first_name surname cell city location_x location_y
1 Paul Miller 447557505611 London 45.123 47.232
Users
#MDBlocal @Lauren_Schaef

26. Collections vs Tables
{
first_name: "Paul",
surname: "Miller",
cell: "447557505611",
city: "London",
location: [45.123,47.232],
profession: ["banking", "finance", "trader"],
cars: [
{
model: "Bentley",
year: 1973
},
{
model: "Rolls Royce",
year: 1965
}
]
}
{
first_name: ”Lauren",
surname: ”Schaefer",
cell: ”1235552222",
city: ”Lancaster",
profession: [”software engineer", ”developer advocate"],
}
{
first_name: ”Sydney",
surname: ”Schaefer",
city: ”Lancaster",
school: ”Daisy’s Daycare”
}
ID first_name surname cell city location_x location_y
1 Paul Miller 447557505611 London 45.123 47.232
2 Lauren Schaefer 1235552222 Lancaster NULL NULL
3 Sydney Schaefer NULL Lancaster NULL NULL
UsersUsers
#MDBlocal @Lauren_Schaef

27. ID first_name surname cell city location_x location_y
1 Paul Miller 447557505611 London 45.123 47.232
2 Lauren Schaefer 1235552222 Lancaster NULL NULL
3 Sydney Schaefer NULL Lancaster NULL NULL
Collections vs Tables
{
first_name: "Paul",
surname: "Miller",
cell: "447557505611",
city: "London",
location: [45.123,47.232],
profession: ["banking", "finance", "trader"],
cars: [
{
model: "Bentley",
year: 1973
},
{
model: "Rolls Royce",
year: 1965
}
]
}
{
first_name: ”Lauren",
surname: ”Schaefer",
cell: ”1235552222",
city: ”Lancaster",
profession: [”software engineer", ”developer advocate"],
}
{
first_name: ”Sydney",
surname: ”Schaefer",
city: ”Lancaster",
school: ”Daisy’s Daycare”
}
UsersUsers
#MDBlocal @Lauren_Schaef

28. Collections vs Tables
ID first_name surname cell city location_x location_y
1 Paul Miller 447557505611 London 45.123 47.232
2 Lauren Schaefer 1235552222 Lancaster NULL NULL
3 Sydney Schaefer NULL Lancaster NULL NULL
{
first_name: "Paul",
surname: "Miller",
cell: "447557505611",
city: "London",
location: [45.123,47.232],
profession: ["banking", "finance", "trader"],
cars: [
{
model: "Bentley",
year: 1973
},
{
model: "Rolls Royce",
year: 1965
}
]
}
{
first_name: ”Lauren",
surname: ”Schaefer",
cell: ”1235552222",
city: ”Lancaster",
profession: [”software engineer", ”developer advocate"],
}
{
first_name: ”Sydney",
surname: ”Schaefer",
city: ”Lancaster",
school: ”Daisy’s Daycare”
}
UsersUsers
#MDBlocal @Lauren_Schaef

29. Schemaless
database
#MDBlocal @Lauren_Schaef

30. Schemaless
database
Don’t panic!
Use schema validation.
#MDBlocal @Lauren_Schaef

31. Document Row
{
...
a: “b”
...
}
ID a ...
1 b ...
2 ... ...
3 ... ...

32. Document Row(s)
{
...
a: “b”
...
}
ID a ...
1 b ...
2 ... ...
3 ... ...
... ... ...
... ... ...
... ... ...
... ... ...
... ... ...
... ... ...

33. Field Column
ID a ...
1 b ...
2 c ...
3 ... ...
{
...
a: “b”
...
}
{
...
a: “c”
...
}

34. Collection Table
{
...
}
... ... ...
... ... ...
... ... ...
... ... ...
{
...
}
{
...
}

35. Database Database
... ... ...
... ... ...
... ... ...
... ... ...
{
...
}
{
...
}
{
...
}
{
...
}
{
...
}
{
...
}
{
...
}
... ... ...
... ... ...
... ... ...
... ... ...
... ... ...

36. Index Index
{
...
}
{
...
}
{
...
}
{
...
}
... ... ...
... ... ...
... ... ...
... ... ...
... ... ...

37. View View
{
...
}
... ... ...
... ... ...
... ... ...
... ... ...
{
...
}
{
...
}

38. Embedding Join
{
...
a: “b”,
...
c: {
d: “e”
...
},
...
}
ID a ...
1 b ...
2 ... ...
3 ... ...
... d ...
1 e ...
... ... ...

39. Database References Join
ID ... ...
1 ... ...
2 ... ...
3 ... ...
... ... ...
1 ... ...
... ... ...
{
...
}
{
...
}
{
...
}
{
...
}
{
...
}
{
...
}
{
...
}

40. $lookup
(Aggregation Pipeline)
Left Outer Join
ID ... ...
1 ... ...
2 ... ...
3 ... ...
... ... ...
1 ... ...
4 ... ...
{
...
}
{
...
}
{
...
}
{
...
}
{
...
}
{
...
}
{
...
}

41. $graphLookup
(Aggregation Pipeline)
Recursive Common
Table Expressions
{
...
}
... ... ...
... ... ...
... ... ...
... ... ...
{
...
}
{
...
}

42. Multi-Document ACID
Transaction
Multi-Record ACID
Transaction
{
...
}
{
...
}
{
...
}
{
...
}
{
...
}
{
...
}
{
...
}
... ... ...
... ... ...
... ... ...
... ... ...
... ... ...
... ... ...
... ... ...

43. Term mapping summary
x
Row Column Table Database Index Join Join
Left Outer
Join
Recursive
Common Table
Expressions
View Transaction
Document Field Collection Database Index Embedding
Database
References
$lookup $graphLookup View Transaction
#MDBlocal @Lauren_Schaef

44. Make the leap from SQL to MongoDB
1. Map terms & concepts from SQL to MongoDB
2. Discover the 4 humongous advantages of MongoDB
3. Change your mindset in 3 key ways
#MDBlocal @Lauren_Schaef

47. Scale cheaper!
As the size of your database grows, scale horizontally.
#MDBlocal @Lauren_Schaef

48. SQLMongoDB
Query faster!
Stop doing expensive joins to get your data.
ID a ...
1 b ...
2 ... ...
3 ... ...
... ... ...
... ... ...
... ... ...
... ... ...
... ... ...
... ... ...
{
...
a: “b”,
...
c: {
d: “e”
...
},
...
}
#MDBlocal @Lauren_Schaef

49. SQLMongoDB
Pivot easier!
Easily change the shape of your data as your app evolves.
{
a: “b”,
c: “one”,
e: “f”
}
{
a: “b”,
c: 1,
new: “no biggee”
}
ALTER TABLE `mydb`.`letters_table`
DROP COLUMN `e`,
ADD COLUMN `New` VARCHAR(45) NULL AFTER `C`,
CHANGE COLUMN `C` `C` INT NULL DEFAULT NULL ;
#MDBlocal @Lauren_Schaef

50. Program faster!
Documents map to data structures in most popular languages.
Update Your Profile
#MDBlocal @Lauren_Schaef

51. Program faster!
{
first_name: "Paul",
surname: "Miller",
cell: "447557505611",
city: "London",
location: [45.123,47.232],
profession: ["banking", "finance", "trader"],
}
ID first_name surname cell city location_x location_y
1 Paul Miller 447557505611 London 45.123 47.232
Users
ID user_id profession
10 1 banking
11 1 finance
12 1 trader
Professions
#MDBlocal @Lauren_Schaef

52. Program faster!
import pymongo
from pymongo import MongoClient
# CONNECT TO THE DB
client = MongoClient()
client =
pymongo.MongoClient("mongodb+srv://
username:password@cluster0nsdia.
mongodb.net/test?retryWrites=true")
db = client.fabapp
# THE ID OF THE USER WHOSE PROFILE WE
# WILL BE RETRIEVING AND UPDATING
userId = 1
import mysql.connector
# CONNECT TO THE DB
mydb = mysql.connector.connect(
host="localhost",
user=”username",
passwd=”password",
database=”fabapp”
)
mycursor = mydb.cursor()
# THE ID OF THE USER WHOSE PROFILE WE
# WILL BE RETRIEVING AND UPDATING
userId = 1

53. Program faster!
# GET THE USER'S PROFILE INFORMATION
## We can pull all of the info from
## the same document since we used
## embedding
user =
db['Users'].find_one({"_id":userId})
# GET THE USER'S PROFILE INFORMATION
### Pull the info from the Users table
### & put it in the user dictionary
sql = "Select * FROM Users WHERE
Users.ID=%s”
values = (userId,)
mycursor.execute(sql, values)
result = mycursor.fetchone()
user = {
"first_name": result[1],
"surname": result[2],
"cell": result[3],
"city": result[4],
"location_x": result[5],
"location_y": result[6]
}
### Pull the info from the Professions
### table & put it in the user dict.
sql = "Select * FROM Professions WHERE
Professions.user_id=%s”
values = (userId,)
mycursor.execute(sql, values)
results = mycursor.fetchall()
professions = []
for result in results:
professions.append(result[2])
user["professions"] = professions

54. Program faster!
# UPDATE THE USER DICTIONARY BASED ON
# USER INPUT IN THE APP
### We'll update the user dictionary
### manually for simplicity
user = {
"first_name": "NewFirst",
"surname": "NewSurname",
"cell": "123-456-7890",
"city": "NewCity",
"location": [40.762, -73.979],
"professions": ["Manager",
"Engineer"]
}
# UPDATE THE USER DICTIONARY BASED ON
# USER INPUT IN THE APP
### We'll update the user dictionary
### manually for simplicity
user = {
"first_name": "NewFirst",
"surname": "NewSurname",
"cell": "123-456-7890",
"city": "NewCity",
"location_x": 40.762,
"location_y": 73.979,
"professions": ["Manager",
"Engineer"]
}

55. Program faster!
# UPDATE THE USER'S PROFILE IN THE DB
### Since the user's data is stored in
### a single document, we only have to
### make one update
result = db['Users'].update_one(
{"_id": userId}, {"$set": user})
# UPDATE THE USER'S PROFILE IN THE DB
### First update what is stored in the
### Users table
sql = "UPDATE Users SET first_name=%s,
surname=%s, cell=%s, city=%s,
location_x=%s, location_y=%s
WHERE (ID=%s)"
values = (
user["first_name"],
user["surname"],
user["cell"],
user["city"],
user["location_x"],
user["location_y"],
userId)
mycursor.execute(sql, values)
mydb.commit()
### Delete existing records in
### Professions table and add new ones
sql = "DELETE FROM Professions WHERE
user_id=%s”
values = (userId,)
mycursor.execute(sql, values)
mydb.commit()
if(len(user["professions"]) > 0):
sql = "INSERT INTO Professions
(user_id,profession) VALUES
(%s, %s)”
values = []
for profession in user["professions"]:
values.append((userId, profession))
mycursor.executemany(sql,values)
mydb.commit()

56. Program faster!
30 lines of code 73 lines of code

57. Make the leap from SQL to MongoDB
1. Map terms & concepts from SQL to MongoDB
2. Discover the 4 humongous advantages of MongoDB
3. Change your mindset in 3 key ways
#MDBlocal @Lauren_Schaef

60. Embrace document diversity
#MDBlocal @Lauren_Schaef

61. Embrace document diversity
The Polymorphic Pattern
{
first_name: "Paul",
surname: "Miller",
cell: "447557505611",
city: "London",
location: [45.123,47.232],
profession: ["banking", "finance", "trader"],
cars: [
{
model: "Bentley",
year: 1973
},
{
model: "Rolls Royce",
year: 1965
}
]
}
{
first_name: ”Lauren",
surname: ”Schaefer",
cell: ”1235552222",
city: ”Lancaster",
profession: [”software engineer", ”developer advocate"],
}
{
first_name: ”Sydney",
surname: ”Schaefer",
city: ”Lancaster",
school: ”Daisy’s Daycare”
}
#MDBlocal @Lauren_Schaef

62. Embrace document diversity
The Outlier Pattern
{
_id: ”Lauren_Schaefer",
displayName: ”Lauren Schaefer",
numFollowers: 1310
followers: [
“naomi_pen”,
“kenwalger”,
“mylynn”
...
]
}
{
_id: ”Nick_Offerman",
displayName: ”Nick Offerman",
numFollowers: 1730332
followers: [
“c_hotaling”,
“IAmJerdog”,
“ChloeCondon”
...
],
has_extras: true
}
{
_id: ”Nick_Offerman_1",
twitter_id: “Nick_Offerman”,
is_overflow: true,
followers: [
“StephenAtHome”,
“TheEllenShow”,
“hulu”
...
]
}
#MDBlocal @Lauren_Schaef

63. Data that is accessed together
should be stored together
#MDBlocal @Lauren_Schaef

64. Data that is accessed together
should be stored together
#MDBlocal @Lauren_Schaef

65. 0
20000
40000
60000
80000
100000
120000
1985 2017
Storage vs Developer Costs
Storage Cost per GB Developer Salary
Data that is accessed together
should be stored together
#MDBlocal @Lauren_Schaef

66. Don’t normalize your data for the sake of normalizing it.
{
a: “b”,
c: {
d: “e”
...
},
f: [“g”, “h”, “i”],
j: [
{
k: “l”
},
{
m: “n”
}
]
}
Data that is accessed together
should be stored together
#MDBlocal @Lauren_Schaef

67. Tread carefully with transactions
Relying on transactions is a bad design smell.
{
...
}
{
...
}
{
...
}
{
...
}
{
...
}
{
...
}
{
...
}
#MDBlocal @Lauren_Schaef

68. Make the leap from SQL to MongoDB
#MDBlocal @Lauren_Schaef

69. Make the leap from SQL to MongoDB
1. Map terms & concepts from SQL to MongoDB
x
Row Column Table Database Index Join Join
Left Outer
Join
Recursive
Common Table
Expressions
View Transaction
Document Field Collection Database Index Embedding
Database
References
$lookup $graphLookup View Transaction
#MDBlocal @Lauren_Schaef

70. Make the leap from SQL to MongoDB
1. Map terms & concepts from SQL to MongoDB
2. Discover the 4 humongous advantages of MongoDB
#MDBlocal @Lauren_Schaef

71. Make the leap from SQL to
MongoDB1. Map terms & concepts from SQL to MongoDB
2. Discover the 4 humongous advantages of MongoDB
1. Scale cheaper
#MDBlocal @Lauren_Schaef

72. Make the leap from SQL to MongoDB
1. Map terms & concepts from SQL to MongoDB
2. Discover the 4 humongous advantages of MongoDB
1. Scale cheaper
2. Query faster
#MDBlocal @Lauren_Schaef

73. Make the leap from SQL to MongoDB
1. Map terms & concepts from SQL to MongoDB
2. Discover the 4 humongous advantages of MongoDB
1. Scale cheaper
2. Query faster
3. Pivot easier
#MDBlocal @Lauren_Schaef

74. Make the leap from SQL to MongoDB
1. Map terms & concepts from SQL to MongoDB
2. Discover the 4 humongous advantages of MongoDB
1. Scale cheaper
2. Query faster
3. Pivot easier
4. Program faster
# GET THE USER'S PROFILE INFORMATION
## We can pull all of the info from
## the same document since we used
## embedding
user =
db['Users'].find_one({"_id":userId})
# GET THE USER'S PROFILE INFORMATION
### Pull the info from the Users table ### &
put it in the user dictionary
sql = "Select * FROM Users WHERE
Users.ID=%s”
values = (userId,)
mycursor.execute(sql, values)
result = mycursor.fetchone()
user = {
"first_name": result[1],
"surname": result[2],
"cell": result[3],
"city": result[4],
"location_x": result[5],
"location_y": result[6]
}
#MDBlocal @Lauren_Schaef

75. Make the leap from SQL to MongoDB
1. Map terms & concepts from SQL to MongoDB
2. Discover the 4 humongous advantages of MongoDB
3. Change your mindset in 3 key ways
#MDBlocal @Lauren_Schaef

76. Make the leap from SQL to MongoDB
1. Map terms & concepts from SQL to MongoDB
2. Discover the 4 humongous advantages of MongoDB
3. Change your mindset in 3 key ways
1. Embrace document diversity
#MDBlocal @Lauren_Schaef

77. Make the leap from SQL to
MongoDB1. Map terms & concepts from SQL to MongoDB
2. Discover the 4 humongous advantages of MongoDB
3. Change your mindset in 3 key ways
1. Embrace document diversity
2. Data that is accessed together should be stored together
Make the leap from SQL to MongoDB
1. Map terms & concepts from SQL to MongoDB
2. Discover the 4 humongous advantages of MongoDB
3. Change your mindset in 3 key ways
1. Embrace document diversity
2. Data that is accessed together should be stored together
#MDBlocal @Lauren_Schaef

78. Make the leap from SQL to MongoDB
1. Map terms & concepts from SQL to MongoDB
2. Discover the 4 humongous advantages of MongoDB
3. Change your mindset in 3 key ways
1. Embrace document diversity
2. Data that is accessed together should be stored together
3. Tread carefully with transactions
#MDBlocal @Lauren_Schaef

79. Don’t be Ron Swanson
(in this particular case)
#MDBlocal @Lauren_Schaef

80. Change your mindset &
get the full value of MongoDB
Don’t be Ron Swanson
#MDBlocal @Lauren_Schaef

81. Additional resources on data
modeling patterns
• Advanced Schema Design Patterns (webinar)
• Building with Patterns: A Summary (blog series)
• M320: Data Modeling (MongoDB University Course – brand new!)
#MDBlocal @Lauren_Schaef

82. Additional resources
• The MongoDB Docs
• JSON Schema Validation – Locking down your model the smart way
• JSON Schema Validation - Checking Your Arrays
• M121: The MongoDB Aggregation Framework
#MDBlocal @Lauren_Schaef

83. Don’t be Ron Swanson
(in this particular case)
Change your mindset and get the
full value of MongoDB
Change your mindset &
get the full value of MongoDB
Get the slides on my Twitter
page: @Lauren_Schaefer
#MDBlocal @Lauren_Schaef

84. Thank You!