title: Stop users overwriting each other
body: <p>I'm wanting to stop two users accidently overwriting each other when updating a record. That is to say two users load a page with record A on it. User one updates record to AB and user two updates it to AC. </p>
  
  <p>I don't just want the last to hit the database to override. I need a mechanism to say the record has been updated so yours can't be saved.</p>
  
  <p>Now the two ideas I have is to time stamp the records and check that. If it doesn't match up don't allow the update. The second method is to GUID the record each time an update is performed, check the GUID and if it doesn't match don't update.</p>
  
  <p>Are either of these methods valid, if so, which is best. If not, what do you suggest. This is in C# if it makes a difference</p>
  
  <p>Thanks</p>