1 files changed, 4 insertions, 2 deletions
diff --git a/activerecord/lib/active_record/attribute_methods/primary_key.rb b/activerecord/lib/active_record/attribute_methods/primary_key.rb
index 63c059e291..d8fc046e10 100644
--- a/activerecord/lib/active_record/attribute_methods/primary_key.rb
+++ b/activerecord/lib/active_record/attribute_methods/primary_key.rb
@@ -17,13 +17,15 @@ module ActiveRecord
       # Returns the primary key value.
       def id
         sync_with_transaction_state
-        _read_attribute(self.class.primary_key) if self.class.primary_key
+        primary_key = self.class.primary_key
+        _read_attribute(primary_key) if primary_key
       end
 
       # Sets the primary key value.
       def id=(value)
         sync_with_transaction_state
-        _write_attribute(self.class.primary_key, value) if self.class.primary_key
+        primary_key = self.class.primary_key
+        _write_attribute(primary_key, value) if primary_key
       end
 
       # Queries the primary key value.