<alter_user_statement>
::=
ALTER USER <user_name>
[<user_mode>]
[TIMEOUT <unsigned_integer>
| TIMEOUT NULL]
[COSTWARNING <unsigned_integer> | COSTWARNING
NULL]
[COSTLIMIT <unsigned_integer> | COSTLIMIT
NULL]
[DEFAULT ROLE ALL [EXCEPT <role_name>] |
DEFAULT ROLE NONE
| DEFAULT ROLE <role_name> [IDENTIFIED BY <password>]]
[[NOT] EXCLUSIVE]
[DEFAULTCODE <ASCII |
UNICODE>]