Last modified 6 years ago

Og Evaluation

(Old evaluation, 2005-05)

Prerequisites

Installation

  • cmd> gem install og [accept dependencies install]
  • cmd> gem install sqlite3 [select latest version for your OS]

Creating the Project

  • Create folder cars
  • Create file cars.rb
  • Create file main.rb
  • Copy og-evolve.rb into cars

Creating a Simple Class

  • Definition
    • Within file cars.rb, use any editor to insert this:: 
      require 'og'
require 'og-evolve'

class Car
  prop_accessor :manufacturer, String
  prop_accessor :model, String
  prop_accessor :modelYear, Fixnum
end

  • Preparation none
  • Deployment none
  • Usage 
    # main.rb

require 'cars'

db = Og::Database.new(
   :database => 'jampersist',
   :adapter => 'sqlite',
   :user => 'user',
   :password => 'password'
)

if Car.all.size == 0
    car1 = Car.new()
    car1.manufacturer = 'Ford'

    car1.model = 'Mustang'
    car1.modelYear = 1990
    car1.save()
end

Adding an 1:1 Relation

  • Declaration
    • Add class Owner (within cars.rb) 
      class Owner
    prop_accessor :name,  String
    prop_accessor :proficiency, String
    has_one :car, Car

    def initialize(name='', proficiency='')
        @name = name
        @proficiency = proficiency
    end
end
  • Add a "1:1" relation to Car 
    class Car
  belongs_to :owner, Owner
end

  • Preparation
    • none
  • Deployment
    • none
  • Usage 
    # main.rb

if Owner.all.size == 0
    Owner.create('Paul')
    peter = Owner.new('Peter')
    peter.save()

    car = Car[1]
    car.owner = peter
    car.save()
end

Adding a 1:N Relation

  • Declaration
    • Add class Driver 
      class Driver
    prop_accessor :name, String
    prop_accessor :licenseType, String
    belongs_to :car, Car
    
    def initialize(name='', licenseType=nil)
        @name = name
        @licenseType = licenseType
    end  
end
  • Add "1:n" relation to Car. 
    class Car
   ...
   has_many :drivers, Driver

  • Preparation
    • none
  • Deployment
    • none
  • Usage 
    # main.rb

if Driver.all.size == 0
    Driver.new('Fred', 'heavy').save()
    Driver.create('Frank', 'normal')

    fred = Driver['Fred']
    frank = Driver['Frank']
        
    car = Car[1]        
    car.add_driver(fred)
    car.add_driver(frank)       
end

Adding a M:N Relation

  • Declaration
    • Add class Road
    • Add class Trip
    • Add "m:n" relation to Cars / Roads. 
      # main.rb

if Driver.all.size == 0
    Driver.new('Fred', 'heavy').save()
    Driver.create('Frank', 'normal')

    fred = Driver['Fred']
    frank = Driver['Frank']
        
    car = Car[1]        
    car.add_driver(fred)
    car.add_driver(frank)       
end
  • Preparation
    • none
  • Deployment
    • none
  • Usage
    • cmd>

Mailinglist Topic

Attachments

  • og-evolve.rb Download (5.3 KB) - added by lazaridis_com 6 years ago. persist.ruby.og schema-evolution support