anchor.diff:  
   alter_table
       : ALTER TABLE tableview_name
  -      ( 
  +      (
         | alter_table_properties
         | constraint_clauses
         | column_clauses
  
positive.code:     | NVL
      | ROUND
      | SUM
      ;
negative.code:         | CLOSE DATABASE LINK parameter_name
          | enable_or_disable COMMIT IN PROCEDURE
          | enable_or_disable GUARD
          | (enable_or_disable | FORCE) PARALLEL (DML | DDL | QUERY) (PARALLEL (literal | parameter_name))?
          | SET alter_session_set_clause
      )
      ;
  
  alter_session_set_clause
      : parameter_name '=' parameter_value
      ;
  
  