title: Why we need isolation in ACID?
body: <p>I am learning ACID, but not quite understand what is the difference between atomic and isolation.</p>
  <p>From my understanding, if a transaction is atomic, that means the integrity of transaction-related data is written to DB when the transaction is succeeded, and not when failed.</p>
  <p><strong>so why we need isolation?</strong></p>
  <p>It can not be seen by others when failed for sure if atomic is guaranteed !?</p>