From 3aafbed39048007c99cb2b1dc9daf734cf4eae66 Mon Sep 17 00:00:00 2001
From: qiangxue <qiang.xue@gmail.com>
Date: Wed, 7 Sep 2016 15:45:16 -0400
Subject: [PATCH] optimization

---
 struct.go | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/struct.go b/struct.go
index 79969d3..5928140 100644
--- a/struct.go
+++ b/struct.go
@@ -100,7 +100,7 @@ func (s *structValue) pk() map[string]interface{} {
 
 // columns returns the struct field values indexed by their corresponding DB column names.
 func (s *structValue) columns(include, exclude []string) map[string]interface{} {
-	v := map[string]interface{}{}
+	v := make(map[string]interface{}, len(s.nameMap))
 	if len(include) == 0 {
 		for _, fi := range s.nameMap {
 			v[fi.dbName] = fi.getValue(s.value)