diff options
Diffstat (limited to 'activerecord/lib/active_record/associations.rb')
| -rw-r--r-- | activerecord/lib/active_record/associations.rb | 50 |
1 files changed, 37 insertions, 13 deletions
diff --git a/activerecord/lib/active_record/associations.rb b/activerecord/lib/active_record/associations.rb index 2605a54cb6..98efdb90c8 100644 --- a/activerecord/lib/active_record/associations.rb +++ b/activerecord/lib/active_record/associations.rb @@ -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 @@ -1087,7 +1107,8 @@ module ActiveRecord # # [:finder_sql] # Specify a complete SQL statement to fetch the association. This is a good way to go for complex - # associations that depend on multiple tables. Note: When this option is used, +find_in_collection+ + # associations that depend on multiple tables. May be supplied as a string or a proc where interpolation is + # required. Note: When this option is used, +find_in_collection+ # is _not_ added. # [:counter_sql] # Specify a complete SQL statement to fetch the size of the association. If <tt>:finder_sql</tt> is @@ -1162,11 +1183,14 @@ module ActiveRecord # has_many :tags, :as => :taggable # has_many :reports, :readonly => true # has_many :subscribers, :through => :subscriptions, :source => :user - # has_many :subscribers, :class_name => "Person", :finder_sql => - # 'SELECT DISTINCT people.* ' + - # 'FROM people p, post_subscriptions ps ' + - # 'WHERE ps.post_id = #{id} AND ps.person_id = p.id ' + - # 'ORDER BY p.first_name' + # has_many :subscribers, :class_name => "Person", :finder_sql => Proc.new { + # %Q{ + # SELECT DISTINCT people.* + # FROM people p, post_subscriptions ps + # WHERE ps.post_id = #{id} AND ps.person_id = p.id + # ORDER BY p.first_name + # } + # } def has_many(name, options = {}, &extension) Builder::HasMany.build(self, name, options, &extension) end @@ -1325,7 +1349,7 @@ module ActiveRecord # # [:class_name] # Specify the class name of the association. Use it only if that name can't be inferred - # from the association name. So <tt>has_one :author</tt> will by default be linked to the Author class, but + # from the association name. So <tt>belongs_to :author</tt> will by default be linked to the Author class, but # if the real class name is Person, you'll have to specify it with this option. # [:conditions] # Specify the conditions that the associated object must meet in order to be included as a +WHERE+ @@ -1420,18 +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)] @@ -1571,7 +1595,7 @@ module ActiveRecord # has_and_belongs_to_many :categories, :join_table => "prods_cats" # has_and_belongs_to_many :categories, :readonly => true # has_and_belongs_to_many :active_projects, :join_table => 'developers_projects', :delete_sql => - # 'DELETE FROM developers_projects WHERE active=1 AND developer_id = #{id} AND project_id = #{record.id}' + # "DELETE FROM developers_projects WHERE active=1 AND developer_id = #{id} AND project_id = #{record.id}" def has_and_belongs_to_many(name, options = {}, &extension) Builder::HasAndBelongsToMany.build(self, name, options, &extension) end |