diff --git a/gorp_test.go b/gorp_test.go
index 355365f..06809e5 100644
--- a/gorp_test.go
+++ b/gorp_test.go
@@ -257,7 +257,7 @@ type DummyFields struct {
 	DummyField175 *[]int64  `db:"-"`
 }
 
-func (s SmartInvoice) DBColumns(columnNames []string) ([]interface{}, error) {
+func (s *SmartInvoice) DBColumns(columnNames []string) ([]interface{}, error) {
 	var columns []interface{}
 	for _, columnName := range columnNames {
 		switch strings.ToLower(columnName) {