Description of the illustration alter_external_table.eps

{ add_column_clause
| modify_column_clauses
| drop_column_clause
| parallel_clause
| external_table_data_props
| REJECT LIMIT { integer | UNLIMITED }
| PROJECT COLUMN { ALL | REFERENCED }
}
  [ add_column_clause
  | modify_column_clauses
  | drop_column_clause
  | parallel_clause
  | external_table_data_props
  | REJECT LIMIT { integer | UNLIMITED }
  | PROJECT COLUMN { ALL | REFERENCED }
  ]...