{ { add_column_clause
  | modify_column_clause
  | drop_column_clause
  }
    [ add_column_clause
    | modify_column_clause
    | drop_column_clause
    ]...
| rename_column_clause
| modify_collection_retrieval
  [ modify_collection_retrieval ]...
| modify_LOB_storage_clause
| alter_varray_col_properties
}