diff --git a/field.go b/field.go
index 7151f468..79e2c0ec 100644
--- a/field.go
+++ b/field.go
@@ -22,35 +22,23 @@ func (field *Field) Set(value interface{}) error {
 		return errors.New("unaddressable value")
 	}
 
-	if rvalue, ok := value.(reflect.Value); ok {
-		value = rvalue.Interface()
+	reflectValue, ok := value.(reflect.Value)
+	if !ok {
+		reflectValue = reflect.ValueOf(value)
 	}
 
-	if scanner, ok := field.Field.Addr().Interface().(sql.Scanner); ok {
-		if v, ok := value.(reflect.Value); ok {
-			if err := scanner.Scan(v.Interface()); err != nil {
-				return err
-			}
-		} else {
-			if err := scanner.Scan(value); err != nil {
-				return err
-			}
-		}
-	} else {
-		reflectValue, ok := value.(reflect.Value)
-		if !ok {
-			reflectValue = reflect.ValueOf(value)
-		}
-
-		if !reflectValue.IsValid() {
-			return nil
-		}
-
+	if reflectValue.IsValid() {
 		if reflectValue.Type().ConvertibleTo(field.Field.Type()) {
 			field.Field.Set(reflectValue.Convert(field.Field.Type()))
+		} else if scanner, ok := field.Field.Addr().Interface().(sql.Scanner); ok {
+			if err := scanner.Scan(reflectValue.Interface()); err != nil {
+				return err
+			}
 		} else {
 			return fmt.Errorf("could not convert argument of field %s from %s to %s", field.Name, reflectValue.Type(), field.Field.Type())
 		}
+	} else {
+		field.Field.Set(reflect.Zero(field.Field.Type()))
 	}
 
 	field.IsBlank = isBlank(field.Field)
diff --git a/main_test.go b/main_test.go
index eb11ddb0..e6c703e4 100644
--- a/main_test.go
+++ b/main_test.go
@@ -228,7 +228,7 @@ func TestTableName(t *testing.T) {
 	DB.SingularTable(false)
 }
 
-func TestSqlNullValue(t *testing.T) {
+func TestNullValues(t *testing.T) {
 	DB.DropTable(&NullValue{})
 	DB.AutoMigrate(&NullValue{})
 
@@ -279,6 +279,30 @@ func TestSqlNullValue(t *testing.T) {
 	}
 }
 
+func TestNullValuesWithFirstOrCreate(t *testing.T) {
+	var nv1 = NullValue{
+		Name:   sql.NullString{String: "first_or_create", Valid: true},
+		Gender: &sql.NullString{String: "M", Valid: true},
+	}
+
+	var nv2 NullValue
+	if err := DB.Where(nv1).FirstOrCreate(&nv2).Error; err != nil {
+		t.Errorf("Should not raise any error, but got %v", err)
+	}
+
+	if nv2.Name.String != "first_or_create" || nv2.Gender.String != "M" {
+		t.Errorf("first or create with nullvalues")
+	}
+
+	if err := DB.Where(nv1).Assign(NullValue{Age: sql.NullInt64{Int64: 18, Valid: true}}).FirstOrCreate(&nv2).Error; err != nil {
+		t.Errorf("Should not raise any error, but got %v", err)
+	}
+
+	if nv2.Age.Int64 != 18 {
+		t.Errorf("should update age to 18")
+	}
+}
+
 func TestTransaction(t *testing.T) {
 	tx := DB.Begin()
 	u := User{Name: "transcation"}
diff --git a/scope_private.go b/scope_private.go
index 761241af..634c1c8a 100644
--- a/scope_private.go
+++ b/scope_private.go
@@ -334,9 +334,8 @@ func (scope *Scope) updatedAttrsWithValues(values map[string]interface{}, ignore
 	}
 
 	var hasExpr bool
-	fields := scope.Fields()
 	for key, value := range values {
-		if field, ok := fields[ToDBName(key)]; ok && field.Field.IsValid() {
+		if field, ok := scope.FieldByName(key); ok && field.Field.IsValid() {
 			if !reflect.DeepEqual(field.Field, reflect.ValueOf(value)) {
 				if _, ok := value.(*expr); ok {
 					hasExpr = true
@@ -347,13 +346,16 @@ func (scope *Scope) updatedAttrsWithValues(values map[string]interface{}, ignore
 			}
 		}
 	}
+
 	if hasExpr {
 		var updateMap = map[string]interface{}{}
-		for key, value := range fields {
-			if v, ok := values[key]; ok {
-				updateMap[key] = v
-			} else {
-				updateMap[key] = value.Field.Interface()
+		for key, field := range scope.Fields() {
+			if field.IsNormal {
+				if v, ok := values[key]; ok {
+					updateMap[key] = v
+				} else {
+					updateMap[key] = field.Field.Interface()
+				}
 			}
 		}
 		return updateMap, true