From 77a1fc6994c4a9e5a3b5a3fa067829bbabf789e5 Mon Sep 17 00:00:00 2001
From: Phillip Shipley <phillip.shipley@gmail.com>
Date: Fri, 13 Jul 2018 10:58:17 -0400
Subject: [PATCH] fix update callback to not try to write zero values when
 field has default value

---
 callback_update.go | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/callback_update.go b/callback_update.go
index 373bd726..bbd78350 100644
--- a/callback_update.go
+++ b/callback_update.go
@@ -76,7 +76,9 @@ func updateCallback(scope *Scope) {
 			for _, field := range scope.Fields() {
 				if scope.changeableField(field) {
 					if !field.IsPrimaryKey && field.IsNormal {
-						sqls = append(sqls, fmt.Sprintf("%v = %v", scope.Quote(field.DBName), scope.AddToVars(field.Field.Interface())))
+						if !field.IsBlank || !field.HasDefaultValue {
+							sqls = append(sqls, fmt.Sprintf("%v = %v", scope.Quote(field.DBName), scope.AddToVars(field.Field.Interface())))
+						}
 					} else if relationship := field.Relationship; relationship != nil && relationship.Kind == "belongs_to" {
 						for _, foreignKey := range relationship.ForeignDBNames {
 							if foreignField, ok := scope.FieldByName(foreignKey); ok && !scope.changeableField(foreignField) {