Add has_many :primary_key option to allow setting the primary key on a has many association

Signed-off-by: Michael Koziarski <michael@koziarski.com>

activerecord/lib/active_record/associations.rb

@@ -663,6 +663,7 @@ module ActiveRecord
       # * <tt>:foreign_key</tt> - Specify the foreign key used for the association. By default this is guessed to be the name
       #   of this class in lower-case and "_id" suffixed. So a Person class that makes a +has_many+ association will use "person_id"
       #   as the default <tt>:foreign_key</tt>.
+      # * <tt>:primary_key</tt> - Specify the method that returns the primary key used for the association. By default this is +id+.
       # * <tt>:dependent</tt> - If set to <tt>:destroy</tt> all the associated objects are destroyed
       #   alongside this object by calling their +destroy+ method.  If set to <tt>:delete_all</tt> all associated
       #   objects are deleted *without* calling their +destroy+ method.  If set to <tt>:nullify</tt> all associated
@@ -678,7 +679,7 @@ module ActiveRecord
       # * <tt>:limit</tt> - An integer determining the limit on the number of rows that should be returned.
       # * <tt>:offset</tt> - An integer determining the offset from where the rows should be fetched. So at 5, it would skip the first 4 rows.
       # * <tt>:select</tt> - By default, this is <tt>*</tt> as in <tt>SELECT * FROM</tt>, but can be changed if you, for example, want to do a join
-      #   but not include the joined columns. Do not forget to include the primary and foreign keys, otherwise it will rise an error.
+      #   but not include the joined columns. Do not forget to include the primary and foreign keys, otherwise it will raise an error.
       # * <tt>:as</tt> - Specifies a polymorphic interface (See <tt>belongs_to</tt>).
       # * <tt>:through</tt> - Specifies a Join Model through which to perform the query.  Options for <tt>:class_name</tt> and <tt>:foreign_key</tt>
       #   are ignored, as the association uses the source reflection. You can only use a <tt>:through</tt> query through a <tt>belongs_to</tt>
@@ -1347,7 +1348,7 @@ module ActiveRecord
 
         def create_has_many_reflection(association_id, options, &extension)
           options.assert_valid_keys(
-            :class_name, :table_name, :foreign_key,
+            :class_name, :table_name, :foreign_key, :primary_key,
             :dependent,
             :select, :conditions, :include, :order, :group, :limit, :offset,
             :as, :through, :source, :source_type,

activerecord/lib/active_record/associations/has_many_association.rb

@@ -19,6 +19,14 @@ module ActiveRecord
       end
 
       protected
+        def owner_quoted_id
+          if @reflection.options[:primary_key]
+            quote_value(@owner.send(@reflection.options[:primary_key]))
+          else
+            @owner.quoted_id
+          end
+        end
+
         def count_records
           count = if has_cached_counter?
             @owner.send(:read_attribute, cached_counter_attribute_name)

activerecord/test/cases/associations/has_many_associations_test.rb

@@ -129,6 +129,10 @@ class HasManyAssociationsTest < ActiveRecord::TestCase
     assert_equal "Microsoft", Firm.find(:first).clients_like_ms_with_hash_conditions.first.name
   end
 
+  def test_finding_using_primary_key
+    assert_equal "Summit", Firm.find(:first).clients_using_primary_key.first.name
+  end
+
   def test_finding_using_sql
     firm = Firm.find(:first)
     first_client = firm.clients_using_sql.first

activerecord/test/fixtures/companies.yml

@@ -5,6 +5,7 @@ first_client:
   client_of: 2
   name: Summit
   ruby_type: Client
+  firm_name: 37signals
 
 first_firm:
   id: 1

activerecord/test/models/company.rb

@@ -46,6 +46,8 @@ class Firm < Company
   has_many :clients_using_finder_sql, :class_name => "Client", :finder_sql => 'SELECT * FROM companies WHERE 1=1'
   has_many :plain_clients, :class_name => 'Client'
   has_many :readonly_clients, :class_name => 'Client', :readonly => true
+  has_many :clients_using_primary_key, :class_name => 'Client',
+           :primary_key => 'name', :foreign_key => 'firm_name'
 
   has_one :account, :foreign_key => "firm_id", :dependent => :destroy, :validate => true
   has_one :unvalidated_account, :foreign_key => "firm_id", :class_name => 'Account', :validate => false

activerecord/test/schema/schema.rb

@@ -102,6 +102,7 @@ ActiveRecord::Schema.define do
     t.string  :type
     t.string  :ruby_type
     t.integer :firm_id
+    t.string  :firm_name
     t.string  :name
     t.integer :client_of
     t.integer :rating, :default => 1