Forms 6i: Unpredictable LOV behaviour

Question

Hi,
I'm trying to modify a forms 6i LOV to return a list of custodians based on information that is in the form at this time. The form is tabbed, and the tab I'm using has multiple records - with an LOV in each record. The problem I'm having is that sometimes the LOV will return a long list of custodians, sometimes just a couple, and sometimes none (no data found). Furthermore I always get the same result for each record, even if that record has a different status (HGF,GVS,Project) - A Pool status is supposed to return no results in the LOV, and I have structured the query such, but it returns the same results as the other records.
I thought maybe the LOV wasn't reading the values right from the active record, so I made some temp fields and created an LOV button that first copied the fields of interest from the active record into temp fields located at the bottom, and the called the List_Values, but the LOV displayed exactly the same behaviour. With the current code, listed below, I get a long list of custodians returned by the LOV regardless of which record's LOV I activate.
The code below is the original code without putting in the temp fields. I hope someone can explain why the LOV is behaving like this, and help me to resolve the problem. Here is the code for my LOV:
SELECT distinct RTRIM(surname) || ', ' || given_names name, v.custodian
FROM vbm_hr_emp_driver c, VBM_CUSTODIAN v, VBM_CUSTODIAN vc
WHERE c.employee_no = v.custodian
AND :VBM_VEHICLE_STATUS.STATUS IN ('HGF','GVS','Project')
AND vc.custodian = v.custodian and vc.status = :VBM_VEHICLE_STATUS.STATUS
AND TO_DATE(TO_CHAR(:VBM_VEHICLE_STATUS.FROM_DATE,'dd-MON-yyyy hh24:mi'),'dd-MON-yyyy hh24:mi') >= vc.from_date
AND (TO_DATE(TO_CHAR(:VBM_VEHICLE_STATUS.FROM_DATE,'dd-MON-yyyy hh24:mi'),'dd-MON-yyyy hh24:mi') < vc.to_date
OR vc.to_date IS NULL)
AND (TO_DATE(TO_CHAR(:VBM_VEHICLE_STATUS.TO_DATE,'dd-MON-yyyy hh24:mi'),'dd-MON-yyyy hh24:mi') < vc.to_date
OR TO_DATE(TO_CHAR(:VBM_VEHICLE_STATUS.TO_DATE,'dd-MON-yyyy hh24:mi'),'dd-MON-yyyy hh24:mi') IS NULL)
ORDER BY Name
Is it that LOV's can't be dynamic - ie: they have a predetermined list of results that can't be changed by variables? Please help as this is driving me mad.
Thanks
Adam

Answer 1

AND TO_DATE(TO_CHAR(:VBM_VEHICLE_STATUS.FROM_DATE,'dd-MON-yyyy hh24:mi'),'dd-MON-yyyy hh24:mi')
>= vc.from_date
AND (TO_DATE(TO_CHAR(:VBM_VEHICLE_STATUS.FROM_DATE,'dd-MON-yyyy hh24:mi'),'dd-MON-yyyy hh24:mi')
< vc.to_date
OR vc.to_date IS NULL)
AND (TO_DATE(TO_CHAR(:VBM_VEHICLE_STATUS.TO_DATE,'dd-MON-yyyy hh24:mi'),'dd-MON-yyyy hh24:mi')
< vc.to_date
OR TO_DATE(TO_CHAR(:VBM_VEHICLE_STATUS.TO_DATE,'dd-MON-yyyy hh24:mi'),'dd-MON-yyyy hh24:mi') IS NULL)
That is a terrible mess for date comparison. This is equivalent:
    AND  :VBM_VEHICLE_STATUS.FROM_DATE >= vc.from_date
    AND (:VBM_VEHICLE_STATUS.FROM_DATE  < vc.to_date
                                       OR vc.to_date IS NULL)
    AND (   :VBM_VEHICLE_STATUS.TO_DATE < vc.to_date
         OR :VBM_VEHICLE_STATUS.TO_DATE IS NULL)