MongoDBGetting started, Couch, and MongoMapper

Who am I? Scott Motte / 25 / Perris, CA mid-level rubyist that prefers merb spitresky.com twitter.com/spitresky github.com/scottmotte scott@spitresky.com

Leopard Install (0.9.7) mkdir -p /data/db wget http://downloads.mongodb.org/osx/mongodbosx-i386-0.9.7.tgz sudo tar xvzf mongodb-osx-i386-0.9.7.tgz -C /usr/local sudo cp -R /usr/local/mongodb-osx-i386-0.9.7/bin/ /usr/ local/bin

Linux Install (0.9.7) mkdir -p /data/db wget http://downloads.mongodb.org/linux/mongodblinux-x86_64-0.9.6.tgz sudo tar -zxvf mongodb-linux-x86_64-0.9.7.tgz -C /usr/ local sudo chmod 755 -R /usr/local/mongodb-linuxx86_64-0.9.7 sudo cp -R /usr/local/mongodb-linux-x86_64-0.9.7/bin/* / usr/local/bin

Running it sudo mongod run & mongo (mysql-like command line)

use bookstore_development db.books.save({ title: "Ender's Game", description: 'zero gravity and mind games' }) db.books.ndOne()

Mongo or CouchMongodb (C++)drivers bson, document, schema-free Dynamic queries, indexing gridfs (needs an apache/nginx module) RAM Good at the web, faster development time Update in place (good for high update rates) master-master 50s kid

Couchdb (Erlang)REST json, document, schema-free map/reduce attachments http cache Good at the web, slower development time MVCC (fault tolerant, but requires compacting) replication indy kid

*http://www.mongodb.org/display/DOCS/Comparing+Mongo+DB+and+Couch+DB

Mongodb ormsRuby mongo-ruby-driversudo gem install mongodb-mongo sudo gem install mongodb-mongo_ext (c extension)

Python mongo-python-drivereasy_install pymongo (c extension autoinstalled)

active-record-adapterhttp://github.com/-mongodb/activerecord-mongo-adapter

autumnhttp://autumn-orm.org/

mongorecordhttp://github.com/mongodb/mongo-activerecord-ruby

mongo-mapperhttp://github.com/jeffjenkins/mongo-mapper

mongomapperhttp://github.com/jnunemaker/mongomapper

MongoMappersudo gem install mongomapper cong.gem 'jnunemaker-mongomapper' #rails dependency 'jnunemaker-mongomapper' #merb

Modelclass Book include MongoMapper::Document key :title, String key :description, String end

Controllerclass Books < Application def index @books = Book.all display @books end def show(id) @book = Book.nd(id) raise NotFound unless @book display @book end ...

Validationsclass Book include MongoMapper::Document key :title, String key :description, String validates_presence_of :title #validates_numericality_of #validates_length_of #validates_format_of #more end

*http://github.com/jnunemaker/validatable

Callbacksclass Book .. key :description, String before_save :append_signature def append_signature self.description @user.id) #fast

Embedded Documentsclass Review include MongoMapper::EmbeddedDocument key :uuid, String, :default => XGen::Mongo::Driver::ObjectID.new key :author, String key :review, String key :created_at, Time, :default => Time.now.utc before_validation do self.uuid = XGen::Mongo::Driver::ObjectID.new end end

*http://groups.google.com/group/mongomapper/browse_thread/thread/178b8c5105ebedd8

Embedded Docs cont.class Reviews < Application .. def create(review) @ight = Flight.nd(params['ight_id']) @review = Review.new(review) if @review.valid? && @ight.reviews {:notice => "Review made"} else message[:error] = "Review fail" render :new end end end # in router.rb resources :ights, :identify => :id do resources :reviews, :identify => :uuid end # /ights/:ight_id/comments/new

Additional info created_at and updated_at are includedautomatically by MongoMapper

_id cannot currently be set withlike in couchrest.

MongoMapper like it can in Couchrest

cannot currently do @doc[custom_eld] indexing: @doc.ensure_index :login

ConclusionMongodb is a great trade off of speed, features, and schema-less freedom, and it now has its developer friendly orm - mongomapper. Strongly consider using it in a web app you otherwise by default would use mysql. Then put together your models and use script/server or bin/merb -i to test your performance improvements. ~ Scott Motte