Databases and Agile Development

Dwight MerrimanMongoDB

•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”?

New data models create an opportunity to innovate

Dynamic schemas

Facilitate agile

But there is a schema!

It evolves some of course

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

{ _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” }, … ]}

{ _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” } )

{ _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’]}

{ _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”} })

Static vs Dynamic

int x = “abc”; // javavar x = “abc”; // javascript

Static vs Dynamic

int x = “abc”; // javavar x = “abc”; // javascript

UPDATE items SET x = “abc”

SOA & Agile

A

B

C

D

{ x : 3, desc : “thing”}

SOA & Agile

A

B

C

D

{ x : 3, desc : “thing”, loc : [20.3, 24.732]}

Further thoughts on writing apps today

Store first, ask questions later“speculative storage”

Further thoughts on writing apps today

Default to real-time

Thanks