diff options
Diffstat (limited to 'activerecord/lib/active_record/associations.rb')
| -rw-r--r-- | activerecord/lib/active_record/associations.rb | 34 |
1 files changed, 27 insertions, 7 deletions
diff --git a/activerecord/lib/active_record/associations.rb b/activerecord/lib/active_record/associations.rb index 0952ea2829..0efa111d12 100644 --- a/activerecord/lib/active_record/associations.rb +++ b/activerecord/lib/active_record/associations.rb @@ -70,7 +70,7 @@ module ActiveRecord end end - class HasManyThroughNestedAssociationsAreReadonly < ActiveRecordError #:nodoc + class HasManyThroughNestedAssociationsAreReadonly < ActiveRecordError #:nodoc: def initialize(owner, reflection) super("Cannot modify association '#{owner.class.name}##{reflection.name}' because it goes through more than one other association.") end @@ -196,6 +196,26 @@ module ActiveRecord # * <tt>Project#categories.empty?, Project#categories.size, Project#categories, Project#categories<<(category1),</tt> # <tt>Project#categories.delete(category1)</tt> # + # === Overriding generated methods + # + # Association methods are generated in a module that is included into the model class, + # which allows you to easily override with your own methods and call the original + # generated method with +super+. For example: + # + # class Car < ActiveRecord::Base + # belongs_to :owner + # belongs_to :old_owner + # def owner=(new_owner) + # self.old_owner = self.owner + # super + # end + # end + # + # If your model class is <tt>Project</tt>, the module is + # named <tt>Project::GeneratedFeatureMethods</tt>. The GeneratedFeatureMethods module is + # included in the model class immediately after the (anonymous) generated attributes methods + # module, meaning an association will override the methods for an attribute with the same name. + # # === A word of warning # # Don't create associations that have the same name as instance methods of @@ -1165,7 +1185,7 @@ module ActiveRecord # has_many :subscribers, :through => :subscriptions, :source => :user # has_many :subscribers, :class_name => "Person", :finder_sql => Proc.new { # %Q{ - # SELECT DISTINCT people.* + # SELECT DISTINCT * # FROM people p, post_subscriptions ps # WHERE ps.post_id = #{id} AND ps.person_id = p.id # ORDER BY p.first_name @@ -1424,18 +1444,18 @@ module ActiveRecord # join table with a migration such as this: # # class CreateDevelopersProjectsJoinTable < ActiveRecord::Migration - # def self.up + # def change # create_table :developers_projects, :id => false do |t| # t.integer :developer_id # t.integer :project_id # end # end - # - # def self.down - # drop_table :developers_projects - # end # end # + # It's also a good idea to add indexes to each of those columns to speed up the joins process. + # However, in MySQL it is advised to add a compound index for both of the columns as MySQL only + # uses one index per table during the lookup. + # # Adds the following methods for retrieval and query: # # [collection(force_reload = false)] |