anchor.diff:   schema_element
    base_table_def
    drop_table_def
  + % alter_user_def
    base_table_element_commalist
    base_table_element
    column_def
  
positive.code: manipulative_statement -> update_statement_searched                                             : '$1'.
  manipulative_statement -> base_table_def                                                        : '$1'.
  manipulative_statement -> drop_table_def                                                        : '$1'.
  manipulative_statement -> view_def                                                              : '$1'.
  
  close_statement -> CLOSE cursor                                                                 : {'close', '$2'}.
  
negative.code:  UNLOCK
   QUOTA
   UNLIMITED
   ALTER
   'AND'
   'NOT'
   'OR'
  