Issues with user/system oracle role access and permissions - oracle

Question

I am having a bit of an odd issue when it comes to oracle roles and my schema creation code, I will do my best to describe my problem below:
On schema create a role is created using the schema name provided.
EXECUTE IMMEDIATE 'CREATE ROLE ' || USER || 'ADMIN_R';
This role is then granted to specific users associated with that schema.
DECLARE
V_ROLE_NAME CONSTANT VARCHAR2(30) := USER || 'ADMIN_R';
CURSOR C_ADMIN_USERS IS
SELECT USERNAME FROM DBUSERS WHERE ROLE = 'ADMINISTRATION';
BEGIN
FOR REC IN C_ADMIN_USERS
LOOP
EXECUTE IMMEDIATE 'GRANT ' || V_ROLE_NAME || ' TO ' || REC.USERNAME || ' WITH ADMIN OPTION';
END LOOP;
END;
Users with this role have access to a special administration package.
EXECUTE IMMEDIATE 'GRANT EXECUTE ON P_ADMINISTRATION TO ' || USER || 'ADMIN_R';
The problem is When I drop the schema it does not drop this role (belongs to oracle), so when I recreate this schema the whole process fails because this role already exists. I also can't grant access to this role without logging into the system users which I want to avoid. The simple solution would be to just drop it, but my concern in that instance is that the DBA has been using that role to grant access to additional users and potentially additional packages, which would all be lost if we just arbitrarily drop the role to recreate it.
Any assistance would be greatly appreciated.

Answer 1

You could surround your role create with something like this:
SELECT COUNT(*)
INTO v_count
FROM DBA_ROLES
WHERE ROLE = USER || 'ADMIN_R';
IF v_count = 0 THEN
--grant your roles
END IF;
You can grant the same privilege as many times as you like.

Answer 2

you can drop the role before create
declare
i int;
begin
select count(*) into i
from dba_roles where role = USER||'ADMIN_R';
if (0 != i) then
execute immediate 'drop role '||USER||'ADMIN_R';
dbms_output.put_line('Role ' ||USER||'ADMIN_R has been dropped');
end if;
execute immediate 'create role '||USER||'ADMIN_R';
dbms_output.put_line('Role ' ||USER||'ADMIN_R has been created');
end;
1st try:
Role SCMADMIN_R has been created
2nd try:
Role SCMADMIN_R has been dropped
Role SCMADMIN_R has been created