public void clearKeys(){
  keys.clear();
  uniqueKeys.clear();
  nonKeyColumns.clear();
  nonKeyColumns.addAll(this.allColumns);
}

public void clearKeys ( ) { keys . clear ( ) ; uniqueKeys . clear ( ) ; nonKeyColumns . clear ( ) ; nonKeyColumns . addAll ( this . allColumns ) ; }
reset keys , which also resets non - key columns and unique keys .
