title: DBMS_SCHEDULER.DROP_JOB only if exists
body: <p>I have a sql script that I must run after I import a dump. among other things the script does, it does the following:</p>
  
  <pre><code>BEGIN 
  --remove program          
  SYS.DBMS_SCHEDULER.DROP_PROGRAM(program_name=&gt;'STATISTICS_COLUMNS_PROG',FORCE=&gt;TRUE);
  --remove job
  SYS.DBMS_SCHEDULER.DROP_JOB (job_name =&gt; 'STATISTICS_COLUMNS_JOB');
  END; 
  </code></pre>
  
  <p>Somtimes the job was already dropped in the original schema, the dump comes without the job and the script fails:</p>
  
  <pre><code>ERROR at line 1:
  ORA-27475: "DMP_6633.STATISTICS_SET_COLUMNS_JOB" must be a job 
  ORA-06512: at "SYS.DBMS_ISCHED", line 213 
  ORA-06512: at "SYS.DBMS_SCHEDULER", line 657 
  ORA-06512: at line 5 
  </code></pre>
  
  <p>How can I avoid this failure in case the job does not exists but still be able to drop it if it is?</p>