修改角色

GRANT obj_privilege ON obj_clause TO role_name [WITH GRANT OPTION];
 
obj_privilege:
    ALTER
  | DELETE
  | INSERT
  | SELECT 
  | UPDATE
  | EXECUTE

obj_clause:
  relation_name
  | relation_name '.' relation_name
  | DIRECTORY relation_name

GRANT {system_privilege_list | ALL PRIVILEGES}
    TO role_name [WITH {GRANT | ADMID} OPTION];

 system_privilege:
    CREATE SESSION
  | EXEMPT REDACTION POLICY
  | SYSDBA
  | SYSOPER
  | SYSBACKUP
  | CREATE TABLE
  | CREATE ANY TABLE
  | ALTER ANY TABLE
  | BACKUP ANY TABLE
  | DROP ANY TABLE
  | LOCK ANY TABLE
  | COMMENT ANY TABLE
  | SELECT ANY TABLE
  | INSERT ANY TABLE
  | UPDATE ANY TABLE
  | DELETE ANY TABLE
  | FLASHBACK ANY TABLE
  | CREATE ROLE
  | DROP ANY ROLE
  | GRANT ANY ROLE
  | ALTER ANY ROLE
  | AUDIT ANY
  | GRANT ANY PRIVILEGE
  | GRANT ANY OBJECT PRIVILEGE
  | CREATE ANY INDEX
  | ALTER ANY INDEX
  | DROP ANY INDEX
  | CREATE ANY VIEW
  | DROP ANY VIEW
  | CREATE VIEW
  | SELECT ANY DICTIONARY
  | CREATE PROCEDURE
  | CREATE ANY PROCEDURE
  | ALTER ANY PROCEDURE
  | DROP ANY PROCEDURE
  | EXECUTE ANY PROCEDURE
  | CREATE SYNONYM
  | CREATE ANY SYNONYM
  | DROP ANY SYNONYM
  | CREATE PUBLIC SYNONYM
  | DROP PUBLIC SYNONYM
  | CREATE SEQUENCE
  | CREATE ANY SEQUENCE
  | ALTER ANY SEQUENCE
  | DROP ANY SEQUENCE
  | SELECT ANY SEQUENCE
  | CREATE TRIGGER
  | CREATE ANY TRIGGER
  | ALTER ANY TRIGGER
  | DROP ANY TRIGGER
  | CREATE PROFILE
  | ALTER PROFILE
  | DROP PROFILE
  | CREATE USER
  | ALTER USER
  | DROP USER
  | CREATE TYPE
  | CREATE ANY TYPE
  | ALTER ANY TYPE
  | DROP ANY TYPE
  | EXECUTE ANY TYPE
  | UNDER ANY TYPE
  | PURGE DBA_RECYCLEBIN
  | CREATE ANY OUTLINE
  | ALTER ANY OUTLINE
  | DROP ANY OUTLINE
  | SYSKM
  | CREATE TABLESPACE
  | ALTER TABLESPACE
  | DROP TABLESPACE
  | SHOW PROCESS
  | ALTER SYSTEM
  | CREATE DATABASE LINK
  | CREATE PUBLIC DATABASE LINK
  | DROP DATABASE LINK
  | ALTER SESSION
  | ALTER DATABASE

obclient> GRANT SELECT ON user1.tbl1 TO role1;
Query OK, 0 rows affected

obclient> GRANT [privilege_list] TO PUBLIC;