Error In Executing VPD Policy Function

Question

Hi,
I have 10.2.0.3 DB running on windows. I have created a function to implement
the VPD. Here is code for Function:
Create or Replace FUNCTION vpd_p return varchar2
as
   retn varchar2(50) :=  user;
begin
   if upper(user) = 'P10' then
      retn := 'DEPTNO = 10' ;
   end if;
   if upper(user) = 'SCOTT' then
     retn := 'DEPTNO = 10' ;
   end if;
   if user = 'P20' then
     retn := 'DEPTNO = 10 or DEPTNO = 20' ;
   end if;
    return retn;
end;
end;I add a policy as:
Begin
dbms_rls.add_policy
( 'SCOTT' ,
   'e' , 
   'MY_POLICY',
   'SCOTT' ,
   'vpd_p' , 
   'SELECT'
end;When i am accessing the table on which i applied poliyc i was
getting the following error:
Policy function execution error:
Logon user     : P10
Table/View     : SCOTT.E
Policy name    : MY_POLICY
Policy function: SCOTT.PK_1.VPD_P
ORA-06550: line 1, column 15:
PLS-00306: wrong number or types of arguments in call to 'VPD_P'
ORA-06550: line 1, column 7:
PL/SQL: Statement ignored
*** 2008-02-13 19:49:48.922
Policy function execution error:
Logon user     : P10
Table/View     : SCOTT.E
Policy name    : MY_POLICY
Policy function: SCOTT.PK_1.VPD_P
ORA-06550: line 1, column 7:
PL/SQL: Statement ignoredWhen i modified my function to below code, it works fine:
Create or Replace FUNCTION vpd_p (abc varchar2 , abcd varchar2)
return varchar2
as
   retn varchar2(50) :=  user;
begin
   if upper(user) = 'P10' then
      retn := 'DEPTNO = 10' ;
   end if;
   if upper(user) = 'SCOTT' then
     retn := 'DEPTNO = 10' ;
   end if;
   if user = 'P20' then
     retn := 'DEPTNO = 10 or DEPTNO = 20' ;
   end if;
    return retn;
end;
end;Even if i change the DATATYPE for "abc" or "abcd" variables to NUMBER
it starts giving the same error. So, my query is why we have to pass any
two VARCHAR2 type variables to apply the VPD policy through function,
even when we are not using these variables anywhere. In documentation
also, i can't find any reason for same.
Please suggest any reason for this abnormal behaviour.........

Answer 1

my query is why we have to pass any
two VARCHAR2 type variables to apply the VPD policy through function,
even when we are not using these variables anywhere. In documentation
also, i can't find any reason for same.Look the Usage Notes in the documentation:
* the policy functions which generate dynamic predicates are called by the server. Following is the interface for the function:
FUNCTION policy_function (object_schema IN VARCHAR2, object_name VARCHAR2)
RETURN VARCHAR2
--- object_schema is the schema owning the table of view.
--- object_name is the name of table, view, or synonym to which the policy applies.