Could not set role using exec immediate

Question

sql_stmt := 'SET ROLE :1 IDENTIFIED BY :2';
EXECUTE immediate sql_stmt USING C_name,C_WORD;
=================
ORA-01937: missing or invalid role name
ORA-06512: at "ASAP.PKG_CREDENTIAL_STORE", line 21
01937. 00000 - "missing or invalid role name"
*Cause:    A valid role name was expected.
*Action:   Specify a valid role name.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                       

Answer 1

I don't think that you can use bind variables for DDL statements:
SQL> select * from v$version;
BANNER
Oracle Database 10g Express Edition Release 10.2.0.1.0 - Product
PL/SQL Release 10.2.0.1.0 - Production
CORE    10.2.0.1.0      Production
TNS for 32-bit Windows: Version 10.2.0.1.0 - Production
NLSRTL Version 10.2.0.1.0 - Production
SQL> alter session set nls_language=english;
Session altered.
SQL>
SQL> drop role r;
Role dropped.
SQL>
SQL> create role r;
Role created.
SQL>
SQL> declare
  2  l_role varchar2(30) := 'r';
  3  begin
  4  execute immediate 'set role :1' using l_role;
  5  end;
  6  /
declare
ERROR at line 1:
ORA-01937: missing or invalid role name
ORA-06512: at line 4
SQL> show errors
No errors.
SQL>
SQL>
SQL> begin
  2  execute immediate 'set role r';
  3  end;
  4  /
PL/SQL procedure successfully completed.
SQL> show errors
No errors.