title: Oracle trigger to prevent inserting the new row upon a condition
body: <p>I've found few questions addressing the same question but without a better solution.
  I need to create an Oracle trigger which will prevent new inserts upon a condition, but silently (without raising an error). </p>
  
  <p>Ex : I need to stop inserting rows with bar='FOO' only. (I can't edit the constraints of the table, can't access the procedure which really does the insertion etc so the trigger is the only option)</p>
  
  <p>Solutions so far confirms that it isn't possible. One promising suggestion was to create an intermediate table, insert key values to that when bar='FOO' and then delete those records from original table once insertion is done, which is not correct I guess.
  Any answer will be highly appreciated.</p>