CouchDB is a NoSQL database that stores data as JSON documents. It can be accessed via HTTP and uses a RESTful API. Documents are schema-free and the database supports replication and scaling to handle thousands of requests per second. Views allow pre-calculated queries on the database using JavaScript map-reduce functions. Ruby libraries like CouchRest make it easy to interact with CouchDB from Ruby applications. The document recommends using CouchDB as the primary data store and web server, with Ruby handling background tasks rather than the full application logic, and using JavaScript frameworks for the frontend.

1. Couch DB a NoSql database
Federico Ramallo

2. About me
Rails developer
Ruby mentor
Certified Scrum Master
Motorcyclist
Co-founder of Tangosource.

3. What is couchdb?
JSON document server
Accesible ONLY via HTTP
RESTful JSON API
is schema free
Distributed, supports replication
Scales a LOT
Can take 2k request / second VS Ruby that can take 15/20
request / second

4. How to query the database?
What is a View?
Is a pre calculated query on the database using map reduce
Use javascript functions
example of a map function
function(doc) {
if(doc.date && doc.title) {
emit(doc.date, doc.title);
}
}
This is a map function that allows you to filter by all records that
has a title field. a.k.a filter by record type
Is schema free, so could use a type field or NOT

5. How to use it with ruby?
There are several rubygems
couchrest https://rubygems.org/gems/couchrest
couch_potato https://github.com/langalex/couch_potato
couch_foo https://github.com/georgepalmer/couch_foo
couchDB-Ruby http://rubyforge.org/projects/couchdb/
The more they try to abstract from couch, the less powerfull they
are.
I recommend couchrest because:
Is light
Is simillar to couch api

6. Couchrest Example
CouchRest example using couchrest gem
require 'couchrest'
# Connect / create to the database
server = CouchRest.new("http://localhost:5984")
db = server.create_db('my-db')
# Save documents
db.save({'_id' => 'my-doc', 'will-exist' => 'here'})
# Get documents
doc = db.get('my-doc'); doc['will-exist'] #=> 'here'
db.delete(doc)

7. How you could use it for big
applications
Move couchdb as a web server
Use Ruby for everything else hanging for the _changes feed
Use js to interact.
Why?
Because is super fast
Because the browser can have the info locally

8. Use JS frameworks for the
frontend!
Examples:
Backbone.js
Sproutcore
Capuccino
Titanum
Ext.js
The new model is: Browser - Couchdb - Ruby

9. What about ruby?
Use it as backend to run background tasks like:
Sending emails
Authentication

10. Thanks
Thanks! framallo@gmail.com