Display role information
1) Show all roles
SQL>select * from dba_roles;
2) Display the system privileges the role has
SQL>select privilege,admin_option from role_sys_privs where role='role name';
3) Display the object privileges the role has
by querying the data dictionary view dba_tab_privs to view the object privileges or column privileges the role has.
4) Display the roles and default roles
of users. When connecting to the database as a user, Oracle will automatically activate the default roles. By querying the data dictionary view dba_role_privs , all roles and the current default roles of a user can be displayed.
>select granted_role,default_role from dba_role_privs where grantee='username';