user := User{Name: "CreateUserExistingTimestamp"}
	curTime := now.MustParse("2016-01-01")
	user.CreatedAt = curTime
	user.UpdatedAt = curTime
	DB.Save(&user)

	AssertEqual(t, user.CreatedAt, curTime)
	AssertEqual(t, user.UpdatedAt, curTime)

	var newUser User
	DB.First(&newUser, user.ID)

	AssertEqual(t, newUser.CreatedAt, curTime)
	AssertEqual(t, newUser.UpdatedAt, curTime)
}

func (cs *callbacks) Raw() *processor {
	return cs.processors["raw"]
}

func (p *processor) Execute(db *DB) *DB {
	// call scopes
	for len(db.Statement.scopes) > 0 {
		db = db.executeScopes()
	}

	var (
		curTime           = time.Now()
		stmt              = db.Statement
		resetBuildClauses bool
	)

	if len(stmt.BuildClauses) == 0 {
		stmt.BuildClauses = p.Clauses
		resetBuildClauses = true
	}

									switch field.AutoUpdateTime {
									case schema.UnixNanosecond:
										assignment.Value = curTime.UnixNano()
									case schema.UnixMillisecond:
										assignment.Value = curTime.UnixMilli()
									case schema.UnixSecond:
										assignment.Value = curTime.Unix()
									}