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modifiers.rb

Modeifiers in Mongo Model.

Usually if You want to update model You load it, make changes and save it back. But if You want to update only some of attributes there’s more efficient way – modifiers.

In this example we’ll create simpel model and update it using modifiers.

 
require 'mongo/model'

Connecting to test database and cleaning it before starting.

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

Defining game Unit.

 
class Unit
  inherit Mongo::Model
  collection :units

  attr_accessor :name, :life
end

Creating brave Tassadar.

 
tassadar = Unit.create name: 'Tassadar', life: 80

Updating model with modifiers.

 
tassadar.update _inc: {life: -40}
tassadar.reload
p tassadar.life                                  # => 40

There’s also helper on the model class.

 
Unit.update({_id: tassadar._id}, {_inc: {life: -20}})
tassadar.reload
p tassadar.life                                  # => 20

In this example we covered using modifiers.