Domain Model from SQL Antipatterns: Avoiding the Pitfalls of Database Programming

bug_report.rb

# SQL Antipatterns: http://pragprog.com/book/bksqla/sql-antipatterns
# A relationship between a model and a DAO like ActiveRecord should be HAS-A 
# (aggregation) instead of (inheritance). Most frameworks that rely on 
# ActiveRecord assume the IS-A solution. If you model uses DAOs instead of 
# inheriting from the DAO class, then you can design the model to contain all 
# data and code for the domain it's supposed to model--even if it takes 
# multiple database tables to represent it.

# BugReport is a domain object encapsulating:
# * Bugs
# * Accounts
# * Products

class BugReport
  class << self
    def create(attributes={}, reported_by)
      attributes.merge!(:status => "NEW", :reported_by => reported_by)
      Bug.create(attributes)
    end
    
    def assign_user(bug_id, assign_to)
      bug = Bug.find(bug_id)
      bug.assigned_to = assigned_to
      bug.save
    end
    
    def fetch(bug_id)
      Rails.cache.fetch(:bugs, bug_id) do
        Bug.find(bug_id)
      end
    end
    
    def search(status, search_string)
      Rails.cache.fetch(:bug_searches, status, search_string) do
        Bug.includes(:product)
           .where(:status => status)
           .where("bugs.summary like '%?%' OR bugs.description like '%?%'", 
             search_string, search_string)
        end
    end
  end
end