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basics.rb

Basic example of working with Mongo Model.

In this example we’ll create simple model and examine basic CRUD and querying operations.

 
require 'mongo/model'

Connecting to test database and cleaning it before starting.

 
Mongo::Model.default_database_name = :default_test
Mongo::Model.default_database.clear

Let’s define Game Unit. Models are just plain Ruby Objects, there’s no any Attribute Scheme, Types, Proxies, or other complex stuff, just use standard Ruby practices.

 
class Unit

Inheriting our Unit Class from Mongo::Model (the inherit keyword is just a simple shortcut including Module and its ClassMethods).

 
  inherit Mongo::Model

You can specify collection name explicitly or omit it and it will be guessed from the class name.

 
  collection :units

There’s no need to define attributes, just use plain old Ruby technics to of working with objects.

 
  attr_accessor :name, :status, :stats

  def inspect; name end
end

Stats conaining statistics about Unit (it will be embedded into the Unit).

There are no difference between main and embedded objects, all of them are just standard Ruby objects.

 
class Unit::Stats
  inherit Mongo::Model

  attr_accessor :attack, :life, :shield
end

Let’s create two great Heroes.

 
zeratul  = Unit.new name: 'Zeratul',  status: 'alive'
zeratul.stats =  Unit::Stats.new attack: 85, life: 300, shield: 100

tassadar = Unit.new name: 'Tassadar', status: 'dead'
tassadar.stats = Unit::Stats.new attack: 0,  life: 80,  shield: 300

Saving units to database

 
p zeratul.save                                    # => true
p tassadar.save                                   # => true

We made error – mistakenly set Tassadar’s attack as zero, let’s fix it.

 
tassadar.stats.attack = 20
p tassadar.save                                   # => true

Querying, use standard MongoDB query.

 
p Unit.first(name: 'Zeratul')                     # => Zeratul
p Unit.all(name: 'Zeratul')                       # => [Zeratul]
Unit.all name: 'Zeratul' do |unit|
  p unit                                          # => Zeratul
end

Simple dynamic finders (bang versions also availiable).

 
p Unit.by_name('Zeratul')                         # => Zeratul
p Unit.first_by_name('Zeratul')                   # => Zeratul
p Unit.all_by_name('Zeratul')                     # => [Zeratul]

In this example we covered basics of Mongo Model, please go to contents for more samples.