{ ADD add_column_options
| MODIFY modify_column_options
| drop_column_clause
| drop_constraint_clause
| parallel_clause
| external_data_properties 
| REJECT LIMIT { integer | UNLIMITED } 
}
[ ADD add_column_options
| MODIFY modify_column_options
| drop_column_clause
| drop_constraint_clause
| parallel_clause
| external_data_properties 
| REJECT LIMIT { integer | UNLIMITED }
]...

For information on the symbols and conventions of Backus-Naur Form (BNF) syntax, see Appendix A.