diff --git a/association.go b/association.go
index 8c6d9864..a73344fe 100644
--- a/association.go
+++ b/association.go
@@ -267,15 +267,16 @@ func (association *Association) Count() int {
 		query        = scope.DB()
 	)
 
-	if relationship.Kind == "many_to_many" {
+	switch relationship.Kind {
+	case "many_to_many":
 		query = relationship.JoinTableHandler.JoinWith(relationship.JoinTableHandler, query, scope.Value)
-	} else if relationship.Kind == "has_many" || relationship.Kind == "has_one" {
+	case "has_many", "has_one":
 		primaryKeys := scope.getColumnAsArray(relationship.AssociationForeignFieldNames, scope.Value)
 		query = query.Where(
 			fmt.Sprintf("%v IN (%v)", toQueryCondition(scope, relationship.ForeignDBNames), toQueryMarks(primaryKeys)),
 			toQueryValues(primaryKeys)...,
 		)
-	} else if relationship.Kind == "belongs_to" {
+	case "belongs_to":
 		primaryKeys := scope.getColumnAsArray(relationship.ForeignFieldNames, scope.Value)
 		query = query.Where(
 			fmt.Sprintf("%v IN (%v)", toQueryCondition(scope, relationship.AssociationForeignDBNames), toQueryMarks(primaryKeys)),
@@ -367,6 +368,7 @@ func (association *Association) saveAssociations(values ...interface{}) *Associa
 	return association
 }
 
+// setErr set error when the error is not nil. And return Association.
 func (association *Association) setErr(err error) *Association {
 	if err != nil {
 		association.Error = err
diff --git a/field.go b/field.go
index 11c410b0..acd06e20 100644
--- a/field.go
+++ b/field.go
@@ -2,6 +2,7 @@ package gorm
 
 import (
 	"database/sql"
+	"database/sql/driver"
 	"errors"
 	"fmt"
 	"reflect"
@@ -44,7 +45,14 @@ func (field *Field) Set(value interface{}) (err error) {
 			if reflectValue.Type().ConvertibleTo(fieldValue.Type()) {
 				fieldValue.Set(reflectValue.Convert(fieldValue.Type()))
 			} else if scanner, ok := fieldValue.Addr().Interface().(sql.Scanner); ok {
-				err = scanner.Scan(reflectValue.Interface())
+				v := reflectValue.Interface()
+				if valuer, ok := v.(driver.Valuer); ok {
+					if v, err = valuer.Value(); err == nil {
+						err = scanner.Scan(v)
+					}
+				} else {
+					err = scanner.Scan(v)
+				}
 			} else {
 				err = fmt.Errorf("could not convert argument of field %s from %s to %s", field.Name, reflectValue.Type(), fieldValue.Type())
 			}
diff --git a/field_test.go b/field_test.go
index c3afdff5..03a3b3b7 100644
--- a/field_test.go
+++ b/field_test.go
@@ -3,6 +3,7 @@ package gorm_test
 import (
 	"testing"
 
+	"github.com/gofrs/uuid"
 	"github.com/jinzhu/gorm"
 )
 
@@ -47,3 +48,20 @@ func TestCalculateField(t *testing.T) {
 		t.Errorf("should find embedded field's tag settings")
 	}
 }
+
+func TestFieldSet(t *testing.T) {
+	type TestFieldSetNullUUID struct {
+		NullUUID uuid.NullUUID
+	}
+	scope := DB.NewScope(&TestFieldSetNullUUID{})
+	field := scope.Fields()[0]
+	err := field.Set(uuid.FromStringOrNil("3034d44a-da03-11e8-b366-4a00070b9f00"))
+	if err != nil {
+		t.Fatal(err)
+	}
+	if id, ok := field.Field.Addr().Interface().(*uuid.NullUUID); !ok {
+		t.Fatal()
+	} else if !id.Valid || id.UUID.String() != "3034d44a-da03-11e8-b366-4a00070b9f00" {
+		t.Fatal(id)
+	}
+}
diff --git a/scope.go b/scope.go
index 378025bd..806ccb7d 100644
--- a/scope.go
+++ b/scope.go
@@ -68,7 +68,7 @@ func (scope *Scope) Dialect() Dialect {
 
 // Quote used to quote string to escape them for database
 func (scope *Scope) Quote(str string) string {
-	if strings.Index(str, ".") != -1 {
+	if strings.Contains(str, ".") {
 		newStrs := []string{}
 		for _, str := range strings.Split(str, ".") {
 			newStrs = append(newStrs, scope.Dialect().Quote(str))
@@ -330,7 +330,7 @@ func (scope *Scope) TableName() string {
 // QuotedTableName return quoted table name
 func (scope *Scope) QuotedTableName() (name string) {
 	if scope.Search != nil && len(scope.Search.tableName) > 0 {
-		if strings.Index(scope.Search.tableName, " ") != -1 {
+		if strings.Contains(scope.Search.tableName, " ") {
 			return scope.Search.tableName
 		}
 		return scope.Quote(scope.Search.tableName)