title: Keep two databases synchronized with timestamp / rowversion
body: <p>I have a primary database containing table A and a secondary database containing another copy of A. Each time my application starts it checks all the rows of table A in the primary database and updates the rows of A in secondary database.</p>
  
  <p>The need for this ugly behaviour is support for a legacy database however this operation on each start is starting to be very cpu expensive.
  I have found out a timestamp (also called row version by Microsoft) can store when rows have been updated.</p>
  
  <p>My application would need therefore to store the last timestamp of the last modified/inserted row and on successive restarts would only query the primary database for modified rows (or inserted new rows) from the database.</p>
  
  <p>This would considerably speed things up, however how would I deal with deleted rows??
  Thank you</p>
  
  <p><strong>EDIT</strong>: I just noticed I only access the primary database in read-only mode.
  I therefore cannot put a timestamp in the original database and I cannot in any way insert TRIGGERS of sort. </p>
  
  <p>Is there someway I can quickly see what changed in the primary database without modifying it?</p>