for idx, field := range fields {
		if field == nil {
			continue
		}

		if len(joinFields) == 0 || len(joinFields[idx]) == 0 {
			db.AddError(field.Set(db.Statement.Context, reflectValue, values[idx]))
		} else { // joinFields count is larger than 2 when using join
			var isNilPtrValue bool
			var relValue reflect.Value
			// does not contain raw dbname

type Config struct {
	CreateIndexAfterCreateTable bool
	DB                          *gorm.DB
	gorm.Dialector
}

type printSQLLogger struct {
	logger.Interface
}

func (l *printSQLLogger) Trace(ctx context.Context, begin time.Time, fc func() (sql string, rowsAffected int64), err error) {
	sql, _ := fc()
	fmt.Println(sql + ";")
	l.Interface.Trace(ctx, begin, fc, err)
}

// GormDataTypeInterface gorm data type interface

			case reflect.Struct:
				tx.AddError(rel.Field.Set(tx.Statement.Context, data, elem.Interface()))
			case reflect.Slice, reflect.Array:
				if reflectFieldValue.Type().Elem().Kind() == reflect.Ptr {
					tx.AddError(rel.Field.Set(tx.Statement.Context, data, reflect.Append(reflectFieldValue, elem).Interface()))
				} else {
					tx.AddError(rel.Field.Set(tx.Statement.Context, data, reflect.Append(reflectFieldValue, elem.Elem()).Interface()))
				}

				},
			},
		},
	}

	DB.Create(&users)

	query := make([]string, 0)
	sess := DB.Session(&gorm.Session{Logger: Tracer{
		Logger: DB.Config.Logger,
		Test: func(ctx context.Context, begin time.Time, fc func() (sql string, rowsAffected int64), err error) {
			sql, _ := fc()
			query = append(query, sql)
		},
	}})

	var result []User
	err := sess.
		Joins("Manager").