ORA-28112: failed to execute policy function - Error in Application Builder

Question

Hey all,
I've added a policy function to one of my tables and now I'm getting this error when I try to update a report region that references that table.
"Query cannot be parsed within the Builder. If you believe your query is syntactically correct, check the ''generic columns'' checkbox below the region source to proceed without parsing. ORA-28112: failed to execute policy function"
If I remove the policy then everything works fine. My application also runs fine with the policy in place. I just get these errors in the application builder when updating a report or an LOV that references the secure table.
The parsing schema is APPL_USER.
Here is the policy function:
FUNCTION DOCUMENT_TABLE_POLICY (object_schema IN VARCHAR2 DEFAULT NULL
,object_name IN VARCHAR2 DEFAULT NULL)
RETURN VARCHAR2 IS
v_nt_seq NUMBER;
BEGIN
IF user = 'APPL_USER' OR INSTR(user, 'ITFC_') = 1 THEN
RETURN NULL;
END IF;
IF V('APP_USER') IS NOT NULL THEN
IF V('F_NT_SEQ') IS NOT NULL THEN
v_nt_seq := V('F_NT_SEQ');
ELSE
SELECT NT_SEQ
INTO v_nt_seq
FROM APPL_USERS
WHERE UPPER(NT_ID) = UPPER(V('APP_USER'));
END IF;
RETURN '(DOCUMENT_TYPE, MANAGED_BY_ELEMENT, PROGRAM_CODE, CONTRACT_NUMBER) IN (SELECT DISTINCT R.DOCUMENT_TYPE, USL.ELEMENT, USL.PROGRAM_CODE, USL.CONTRACT_NUMBER FROM IPRACA_USERS_SECURITY_LINK USL, IPRACA_SECURITY_ROLES R WHERE R.SECURITY_ROLE_SEQ = USL.SECURITY_ROLE_SEQ AND USL.NT_SEQ = ' || TO_CHAR(v_nt_seq) || ')';
END IF;
--UNAUTHORIZED USERS CAN SEE NO DATA
RETURN '1=0';
END;
This is how I setup the policy:
BEGIN
DBMS_RLS.ADD_POLICY(
object_schema => 'APPL_USER'
,object_name => 'APPL_DOCUMENT'
,policy_name => 'APPL_DOCUMENT_POLICY'
,function_schema => 'APPL_USER'
,policy_function=> 'APPL_SECURITY.DOCUMENT_TABLE_POLICY'
END;
Any help would be greatly appreciated!
Thanks,
Jonathan Hart
APEX 3.1.1

Answer 1

Thanks.
After looking at it again, I think that may be the problem, too. I guess the APP_USER is set when in the application builder and the Builder is running the report query as it is being parsed which is causing the error. I added a Begin - Exception block around that query and everything seems to work now.
Thanks again!