Presented by Nuri Halperin, Owner and Principal, Plus N Consulting Experience level: Deep dive When designing a solution leveraging MongoDB, the entities and business requirements need to be evaluated in a new light. In this session, we'll take a business scenario mapped out the traditional relational way, and synthesize a document oriented solution pitching to Mongo's strengths. We'll examine common tradeoffs and considerations that may arise and demonstrate key mechanics that can be implemented to address them.

1. From Story to
Document
APPLYING MONGO ORIENTED THINKING TO BUSINESS REQUIREMENTS
NURI HALPERIN | MONGODB DAYS SILICON VALLEY 2015

2. Why are we here?

3. MongoDB SQL

4. From Tables to Documents
Document

5. A team story

6. Good News Everyone!

7. "Maker
Space"

8. "Victory!"

9. Let's plan
this!

10. Tables!
Constraints!
Normalization!

11. Person
id UUID
first_name nvarchar(32)
last_name nvarchar(32)

12. Makers are
People!

13. Person
id UUID
first_name nvarchar(32)
last_name nvarchar(32)
Maker
person_id UUID
status_id Int (not null)
Maker Status
id int
status varchar(16)

14. Tool
id UUID
name nvarchar(32)

15. Tool
id UUID
name nvarchar(32)
tool_type_id int
Tool Type
id int
name vharchar
"hand" | "power"

16. Is everything
a tool?

17. Tool
asset_id UUID
tool_type_id int
Tool Type
id int
name vharchar
is_certifiable bit (not null)
Asset
id UUID
name nvarchar(32)
is_stationary bit

18. Certification
id UUID
tool_type_id int
date datetime
Maker Certification
member_id UUID
certification_id UUID
date datetime
Person
id UUID
first_name nvarchar(32)
last_name nvarchar(32)
Tool Type
id int
name vharchar
is_certifiable bit (not null)

19. Tool
asset_id UUID
tool_type_id int
Tool Type
id int
name vharchar
Asset
id UUID
name nvarchar(32)
is_stationary bit
Certification
person_id UUID
tool_type_id UUID
name varchar(16)
Member Certification
member_id UUID
certification_id UUID
date datetime
Member Tool Log
asset_id UUID
type_id int
Person
id UUID
first_name nvarchar(32)
last_name nvarchar(32)
Maker
person_id UUID
status_id Int (not null)
Maker Status
id int
status varchar(16)

20. Must. Not. Overthink.

21. Maker gets certified
Borrow & return tool
Report tool usage

22. Thinking Document
Key interactions drives
document design.

23. Tool
asset_id UUID
type_id int
Tool Type
id int
name vharchar
Asset
id UUID
name nvarchar(32)
is_stationary bit
Certification
person_id UUID
asset_id UUID
name varchar(16)
Member Certification
member_id UUID
certification_id UUID
Member Tool Log
asset_id UUID
type_id int
date datetime
Person
id UUID
first_name nvarchar(32)
last_name nvarchar(32)
Maker
person_id UUID
status_id Int (not null)
Maker Status
id int
status varchar(16)
We can do
anything!

24. Generic
Purpose-
Built

25. {
_id: ObjectId('…'),
name: 'Martha',
}
"Person"

26. {
_id: ObjectId('…'),
name: 'Martha',
status: 'paid'
}
"Person"

27. {
_id: ObjectId('…'),
name: 'Martha',
status: 'paid',
certified: [{t:'cnc', d:'2015-11-26'}],
}
Get Certified

28. {
_id: ObjectId('…'),
name: 'Martha',
status: 'paid',
certified: [{t:'cnc', d:'2015-11-26'}],
}
db.maker.update(
{name: 'Martha', 'certified.t': {$ne:'cnc'}},
{ $push:
{certified: {t:'cnc', d: ISODate()} }
}

29. {
_id: ObjectId('…'),
name: 'Martha',
status: 'paid',
certified: [{t:'cnc', d:'2015-11-26'}],
}
Certification
id UUID
person_id UUID
tool_type_id int
date datetime
Maker Certification
member_id UUID
certification_id UUID
Person
id UUID
first_name nvarchar(32)
last_name nvarchar(32)

30. Thinking Document
Data that works together
lives together.

31. Tables!
Constraints!
Normalization!

32. if ( tool.type != 'hand') {
alert('Certification Required');
}
{ _id: 1, name: 'knife', type: 'hand'}
{ _id: 2, name: 'drill', type: 'power'}
{ _id: 3, name: 'lathe', type: 'stationary'}

33. if ( tool.type != 'hand') {
alert('Certification Required');
}
{ _id: 1, name: 'knife', type: 'hand'}
{ _id: 2, name: 'drill', type: 'power'}
{ _id: 3, name: 'lathe', type: 'stationary'}
{ _id: 4, name: 'scope', type: 'instrument'}
X

34. { _id: 1, name: 'knife', …, req: false}
{ _id: 2, name: 'drill', …, req: true}
{ _id: 3, name: 'lathe', …, req: true}
{ _id: 4, name: 'scope', …, req: true}
There, I fixed it!
if (tool.requiresCertification) {
alert('Certification Required');
}

35. { _id: 1, name: 'knife', type: 'hand'}
{ _id: 2, name: 'drill', type: 'power'}
{ _id: 3, name: 'lathe', type: 'stationary'}
{ _id: 4, name: 'scope', type: 'instrument'}
X
public enum ToolType {
HAND, POWER, STATIONARY
};

36. Extra Field :: Tables
DOWN TIME? COORDINATED DEPLOYMENT?
ALTER TABLE [x]
ADD COLUMN [is_certifiable] bit
DEFAULT 0

37. Extra Field :: MongoDB
FLEXIBLE SCHEMA, CODE FIRST
> db.x.insert({
…,
is_certifiable: true})
> db.x.update(
{_id: 123},
{$set:{is_certifiable: true}})
On the fly!

38. Thinking Document
Embed immutable data.

39. {
_id: 1,
name: 'scope',
borrows: [
{ maker_id: 1, dt: ISODate('2015-06-12'), type: 'out'},
{ maker_id: 1, dt: ISODate('2015-07-04'), type: 'in'},
]
}

40. {
_id: 1,
name: 'scope',
borrows: [
{ maker_id: 1, dt: ISODate('2015-06-12'), type: 'out'},
{ maker_id: 1, dt: ISODate('2015-07-04'), type: 'in'},
]
}
Embed?
Ownership?
Work together?
Bound growth?
Lifetime?

41. {
_id: …,
maker: { _id: 17, name: 'bob' }
tool : { _id: 1, name: 'scope'},
date: ISODate('2015-11-26 18:30Z'),
action: 'out'
}
Check tool in / out
Ledger

42. Maker gets certified
Borrow & return tool
Report tool usage?



43. db.toolLog.aggregate([
{$match: {action: 'out', date: {$gte: ISODate('2015-09-01') }}},
{$group: {_id: "$tool.name", count: {$sum: 1}}},
{$sort: {count: -1}}
]);

44. db.toolLog.aggregate([
{$match: {action: 'out', date: {$gte: ISODate('2015-09-01') }}},
{$group: {_id: "$maker.name", count: {$sum: 1}}},
{$sort: {count: -1}}
]);

45. "Audit
Report"

46. db.toolLog.aggregate([
{$sort: {date: -1}},
{$group: {
_id: "$tool",
action: {$first: "$action"},
at: {$first: "$date"},
by: {$first: "$maker"} }
},
{$match: {action: "out"}},
{$project: {
_id: 0,
"maker": "$by.name",
"has": "$_id.name",
since: "$at",
days: {$divide:[{$subtract: [{$literal: ISODate()}, "$at"]}, 1000*60*60*24]}
}}
]);
"Audit
Report"

47. {
_id: …,
maker: { _id: 17, name: 'bob' }
tool : { _id: 123, name: 'hammer'},
date: ISODate('2015-11-26 18:30Z'),
action: 'check-out'
}
db.toolLog.createindex({
date: 1,
"tool.name": 1
})

48. Thinking Document
Let the engine work for you

49. Tool
asset_id UUID
type_id int
Tool Type
id int
name vharchar
Asset
id UUID
name nvarchar(32)
is_stationary bit
Certification
person_id UUID
asset_id UUID
name varchar(16)
Member Certification
member_id UUID
certification_id UUID
Person
id UUID
first_name nvarchar(32)
last_name nvarchar(32)
Maker
person_id UUID
status_id Int (not null)
Maker Status
id int
status varchar(16)
Member Tool Log
asset_id UUID
type_id int
date datetime

50. maker
tool
toolLog
{
_id: 17,
name: 'bob',
status: 'paid',
certified: [
{t:'cnc', d:'2015-11-26'}
],
}
{
_id: 2,
name: 'drill',
type: 'power',
}
{
_id: 789234,
maker: { _id: 17, name: 'bob' }
tool : { _id: 2, name: 'drill'},
date: ISODate('2015-11-26 18:30Z'),
action: 'check-out'
}

51. Thinking Document
Key interactions drives
document design.

52. Thinking Document
Data that works together
lives together.

53. Thinking Document
Embed immutable data.

54. Thinking Document
Let the engine work for you

55. Thinking Document
*Rules enforced by application.

56. Thank you!
Nuri Halperin
+N Consulting
nuri@plusnconsulting.com
nurih
@nurih