Implicit cascading may not be supported in a future version

  Explanation:  On a DROP TABLE, SQL will currently drop all
  indexes, views triggers and constraints which reference the
  table.  In a future release, these objects will only be dropped
  if you specify CASCADE.  On a DROP VIEW, SQL will currently drop
  all views which references that view.  In a future release, they
  will only be dropped if you specify CASCADE.

  User Action:  If you want these objects to be deleted, specify
  the CASCADE option on the drop.