1. Databases and Agile
Development
Dwight Merriman
MongoDB

2. • What is the first thing you think of when you
hear “RDBMS”?
• What is the first thing you think of when you
hear “SQL”?
• What is the first thing you think of when you
hear “NoSQL”?

3. New data models create an
opportunity to innovate

4. Dynamic schemas
Facilitate agile
But there is a schema!
It evolves some of course

5. {
_id : “too_big_to_fail”,
title : “Too Big to Fail”,
author : “joe123”,
when : “2008-12-03”,
body_text : “…”,
}

6. {
_id : “too_big_to_fail”,
title : “Too Big to Fail”,
author : “joe123”,
when : “2008-12-03”,
body_text : “…”,
comments : [
{ who:”jane”, comment:”I don’t think so…”,
when:”2008-12-04” },
…
]
}

7. {
_id : “too_big_to_fail”,
title : “Too Big to Fail”,
author : “joe123”,
when : “2008-12-03”,
body_text : “…”,
comments : [
{ who:”jane”, comment:”I don’t think so…”,
when:”2008-12-04” },
…
]
}
db.posts.find( { “who”:”jane” } )

8. {
_id : “too_big_to_fail”,
title : “Too Big to Fail”,
author : “joe123”,
when : “2008-12-03”,
body_text : “…”,
comments : [
{ who:”jane”, comment:”I don’t think so…”,
when:”2008-12-04” },
…
],
votes : 3,
voters : [‘joe123’,’kblm’,’dwight’]
}

9. {
_id : “too_big_to_fail”,
title : “Too Big to Fail”,
author : “joe123”,
when : “2008-12-03”,
body_text : “…”,
comments : [
{ who:”jane”, comment:”I don’t think so…”,
when:”2008-12-04” },
…
],
votes : 3,
voters : [‘joe123’,’kblm’,’dwight’]
}
db.posts.update(
{_id:“too_big_to_fail” , voters:{$ne:”jjelm”}},
{$inc:{votes:1},
$push:{voters:”jjelm”}
}
)

10. Static vs Dynamic
int x = “abc”; // java
var x = “abc”; // javascript

11. Static vs Dynamic
int x = “abc”; // java
var x = “abc”; // javascript
UPDATE items SET x = “abc”

12. SOA & Agile
B
A
C
{
x : 3,
desc : “thing”
}
D

13. SOA & Agile
B
A
C
{
x : 3,
desc : “thing”,
loc : [20.3, 24.732]
}
D

14. Further thoughts
on writing apps today
Store first, ask questions later
“speculative storage”

15. Further thoughts
on writing apps today
Default to real-time

16. Thanks