diff --git a/lib/friendly_id/base.rb b/lib/friendly_id/base.rb
index b71552fd9..e3c2a5e53 100644
--- a/lib/friendly_id/base.rb
+++ b/lib/friendly_id/base.rb
@@ -222,7 +222,7 @@ def friendly_id_config
     end
 
     def primary_key_type
-      @primary_key_type ||= columns.find(&:primary).type
+      @primary_key_type ||= columns.find { |c| c.name == primary_key}.type
     end
   end
 
diff --git a/test/slugged_test.rb b/test/slugged_test.rb
index ad50ff17e..1f51c881f 100644
--- a/test/slugged_test.rb
+++ b/test/slugged_test.rb
@@ -265,7 +265,7 @@ def model_class
 
   test "should have a string as a primary key" do
     assert_equal model_class.primary_key, "string_key"
-    assert_equal model_class.columns.find(&:primary).name, "string_key"
+    assert_equal model_class.columns.find { |c| c.name == model_class.primary_key}.name, "string_key"
   end
 
   test "should be findable by the string primary key" do