CouchDB

meetup@cluj.rb ~$ whoami

ls -l /couchdb/

● intro● demo

view /couchdb/lol

head /couchdb/about

Apache CouchDB is a document-oriented database that can be queried and indexed using

JavaScript in a MapReduce fashion.

CouchDB also offers incremental replication with bi-directional conflict detection and resolution.

cat /couchdb/about

CouchDB provides a RESTful JSON API than can be accessed from any environment that allows

HTTP requests.

CouchDB’s built in Web admin console speaks directly to the database using HTTP requests

issued from your browser.

tail /couchdb/about

CouchDB is written in Erlang, a robust functional programming language ideal for building

concurrent distributed systems.

Erlang allows for a flexible design that is easily scalable and readily extensible.

cat /couchdb/history

started in 2005 by Damien Katz

became an Apache project in 2008

currently at version 1.1.1

head /couchdb/how

CouchDB is a document oriented database

data is stored in “documents” and not in “relations” like in an RDBMS

non-locking MVCC and ACID compliant data store

view /couchdb/how

view /couchdb/how

cat /couchdb/how

no SQL

querying is done using “views”

views are defined using Map/Reduce functions

data is indexed using these views as it is stored in the DB

cat /couchdb/how

Map functions emit (key, value) interpretation of the data

Reduce functions aggregate data emitted by map functions

Map/Reduce functions are written in JavaScript or CoffeeScript

head /couchdb/use

good for:

storing documents – or any data which is document-like

hosting entire applications

cat /couchdb/why

very easy to program with – no SQL, no schema, no ORM

schema-less means very easy to deploy changes

easy to administer, backup, replicate, can work offline

tail /couchdb/use

not suitable for:

storing data which is relational in nature

be careful with data that needs to have unique values

view /couchdb/lol

vi /couchdb/doc

{

“_id”: ”BCCD12CBB”,

“_rev”: ”AB764C”,

“type”: ”person”,

“name”: ”Darth Vader”,

“age”: 63,

“headware”:

[“Helmet”, “Sombrero”],

“dark_side”: true

}

cat /couchdb/rest/how

create: HTTP POST /db/BCCD12CBB

read: HTTP GET /db/BCCD12CBB

update: HTTP PUT /db/BCCD12CBB

delete: HTTP DELETE /db/BCCD12CBB

head /couchdb/rest/usage

$ curl -X GET http://server/database/document

{“_id”:”ABC”,“_rev”:”1D4”,”data”:...}

cat /couchdb/tests

silly read-only benchmark with memory saturation

2,500 req/s sustained on a 2Ghz dual core Athlon

using 9.8 mb RAM

exec /couchdb/demo

let's get dirty!

view /couchdb/lol

sudo halt

Q?