title: Error during trigger execution ORA-06512 And ORA-04088
body: <p>I have created a trigger so that the user can not enter a CRIME_NO if it doesn't exist in the CRIME table. which does work i do receive the 'Crime Number: '|| :new.CRIME_NO || ' not in the Crime table') error.</p>
  
  <p>However i also receive ORA-06512: at "C3405016.EVIDENCE_FK", line 8 ORA-04088: error during execution of trigger 'C3405016.EVIDENCE_FK'</p>
  
  <pre><code>Create or replace trigger Evidence_fk
  before insert or update of CRIME_NO
  on Evidence
  for each row
  declare
           dummy   integer;
  begin
           select count(*)    into dummy
           from Evidence
           where CRIME_NO = :new.CRIME_NO;
       if (dummy &lt; 1) /* i.e. no corresponding Crime_No in Crime */
               then raise_application_error(-20002,
               'Crime Number: '|| :new.CRIME_NO || ' not in the Crime table');
           end if;
  end;
  </code></pre>
  
  <p>ORA-20002: Crime Number: 20 not in the Crime table ORA-06512: at "C3405016.EVIDENCE_FK", line 8 ORA-04088: error during execution of trigger 'C3405016.EVIDENCE_FK'</p>