title: Handle concurrency in the user interface when a data record is deleted/updated
body: <p>I would like to know how should I handle the scenarios in the user interface when:</p>
  
  <p>1.) A user deletes a data record which got already deleted by another user</p>
  
  <p>When the data record is already deleted it won`t be deleted anymore and with something like "Delete From Table Where Id = @IdToDelete" nothing bad should happen.</p>
  
  <p>But should I not tell my user instead:"Sorry we could not delete the data record because it got already deleted by user xyz" ??</p>
  
  <p>2.) A user updates a data record which got already modified by another user?
  Should I show for all my update() scenarios a window to the user with the new value and old value and let him choose or decide finally what will win ?</p>