trigger to update timestamp in an sql table

USE [DatabaseName]
GO
SET ANSI_NULLS ON
GO
SET QUOTED_IDENTIFIER ON
GO
ALTER TRIGGER [dbo].[updateLastEditTime]
ON [dbo].[LogonLog]
FOR UPDATE, INSERT
AS
UPDATE LogonLog SET [timestamp] = CURRENT_TIMESTAMP 
FROM LogonLog Inner Join Inserted On
LogonLog.username = Inserted.username
and LogonLog.computername  = Inserted.computername