Revert "Raise error on unknown primary key."

This reverts commit ee2be435b1e5c0e94a4ee93a1a310e0471a77d07.

3 files changed, 4 insertions, 11 deletions

diff --git a/activerecord/lib/active_record/attribute_methods/primary_key.rb b/activerecord/lib/active_record/attribute_methods/primary_key.rb
index 36d7f4ad11..a404a5edd7 100644
--- a/activerecord/lib/active_record/attribute_methods/primary_key.rb
+++ b/activerecord/lib/active_record/attribute_methods/primary_key.rb
@@ -14,8 +14,6 @@ module ActiveRecord
         # primary_key_prefix_type setting, though.
         def primary_key
           @primary_key ||= reset_primary_key
-          raise ActiveRecord::UnknownPrimaryKey.new(self) unless @primary_key
-          @primary_key
         end
 
         # Returns a quoted version of the primary key name, used to construct SQL statements.
@@ -31,11 +29,6 @@ module ActiveRecord
           key
         end
 
-        def primary_key? #:nodoc:
-          @primary_key ||= reset_primary_key
-          !@primary_key.nil?
-        end
-
         def get_primary_key(base_name) #:nodoc:
           return 'id' unless base_name && !base_name.blank?
 
diff --git a/activerecord/lib/active_record/attribute_methods/read.rb b/activerecord/lib/active_record/attribute_methods/read.rb
index 8566ecad14..4174e4da09 100644
--- a/activerecord/lib/active_record/attribute_methods/read.rb
+++ b/activerecord/lib/active_record/attribute_methods/read.rb
@@ -40,7 +40,7 @@ module ActiveRecord
               define_read_method(attr_name, attr_name, columns_hash[attr_name])
             end
 
-            if primary_key? && attr_name == primary_key && attr_name != "id"
+            if attr_name == primary_key && attr_name != "id"
               define_read_method('id', attr_name, columns_hash[attr_name])
             end
           end
@@ -63,7 +63,7 @@ module ActiveRecord
             cast_code = column.type_cast_code('v')
             access_code = "(v=@attributes['#{attr_name}']) && #{cast_code}"
 
-            unless primary_key? && attr_name.to_s == primary_key.to_s
+            unless attr_name.to_s == self.primary_key.to_s
               access_code.insert(0, "missing_attribute('#{attr_name}', caller) unless @attributes.has_key?('#{attr_name}'); ")
             end
 
@@ -107,7 +107,7 @@ module ActiveRecord
 
       def _read_attribute(attr_name)
         attr_name = attr_name.to_s
-        attr_name = self.class.primary_key? && self.class.primary_key if attr_name == 'id'
+        attr_name = self.class.primary_key if attr_name == 'id'
         value = @attributes[attr_name]
         unless value.nil?
           if column = column_for_attribute(attr_name)
diff --git a/activerecord/lib/active_record/attribute_methods/write.rb b/activerecord/lib/active_record/attribute_methods/write.rb
index 4db6d71ba6..e9cdb130db 100644
--- a/activerecord/lib/active_record/attribute_methods/write.rb
+++ b/activerecord/lib/active_record/attribute_methods/write.rb
@@ -18,7 +18,7 @@ module ActiveRecord
               end
             end
 
-            if primary_key? && attr_name == primary_key && attr_name != "id"
+            if attr_name == primary_key && attr_name != "id"
               generated_attribute_methods.module_eval("alias :id= :'#{primary_key}='")
             end
           end