diff --git a/postgresql/collection.go b/postgresql/collection.go
index 76b39a2f79a18359b40e7045d108dfa47d188ccd..c52e6ef9e24f4bd98ee27923e8211e3e2f7a0811 100644
--- a/postgresql/collection.go
+++ b/postgresql/collection.go
@@ -36,7 +36,6 @@ import (
 type table struct {
 	sqlutil.T
 	*database
-	primaryKey string
 }
 
 var _ = db.Collection(&table{})