ction T2 then reads that row and obtains 
 the modified value, before T1 has committed or rolled back. 
 Transaction T2 eventually commits successfully; it does not 
 matter whether T1 commits or rolls back and whether it does 
 so before or after T2 commits.
   </li>
   <li> P2 (Non-repeatable read): Transaction T1 reads a row. 
 Another transaction T2 then modifies or deletes that row, 
 before T1 has committed. Both transactions eventually commit 
 successfully.
   </li>
 </ul>

 <p> Lock modes must alwa