until Transaction B releases
    its read lock on X, but Transaction B cannot make forward progress
    until Transaction A releases its read lock on X.
</p>
      <p>
    In order to detect that deadlock has happened, a separate process or
    thread must review the locks currently held in the database.  If
    deadlock has occurred, a victim must be selected, and that victim will
    then return the error 
    <a class="link" href="program_errorret.html#program_errorret.DB_LOCK_DEADLOCK">DB_LOCK_DEADLOCK<