title: Find non updated records from list of update statements executing in a batch
body: <p>I have a list of update statements which I am executing them in a batch .I need to find non updated values </p>
  
  <p>Eg : My table has 1 , 2 , 3 records . I am running a execute batch for updating records 3 , 4 . execute batch doesn't throw any error as 4 is not present in DB .</p>
  
  <p>Since update statement doesn't return error , if the key doesn't exist in db , we are not able to find 4 in the above case. please help !!!</p>