title: Check for existence or catch exception?
body: <p>I want to update a record if the record exists or insert a new one if it doesn't.</p>
  
  <p>What would be the best approach?</p>
  
  <p>Do a <code>Select Count()</code> and if comes back zero then insert, if one then query the record, modify and update,
  or should I just try to query the record and catch any system.queryexception?</p>
  
  <p>This is all done in Apex, not from REST or the JS API.</p>