title: cannot drop a system-generated sequence
body: <p>I have a system-generated sequence in my Oracle 12c database that I cannot seem to get rid of. Calling "drop sequence" on it gets this error:</p>
  
  <blockquote>
    <p>Error code: ORA-32794<br>
    Description: cannot drop a system-generated sequence<br>
    Cause: An attempt was made to drop a system-generated sequence.<br>
    Action: A system-generated sequence, such as one created for an identity column, cannot be dropped.</p>
  </blockquote>
  
  <p>The sequence was used to generate values for a table's Id column, and the table no longer exists. Usually, I can create and drop such tables and the sequence drops with it. I do not know the statements by which the table was dropped in this instance, but I would really like to remove the stray sequence.</p>