Formula field, Detail records not getting updated

Question

Hello seniors,
i need help on 2 issues;
first, Issue No. 1
i have master-detail form with the following tables;
POH                                  master record table
PH_NO                              pk
PH_PARTY
PH_FXRATE                       exchange rate
PH_PD_LOCAL_TOT           total of PD_LOCAL_AMT  from details records
PH_PD_FOREIGN_TOT       total of PD_FOREIGN_AMT  from details records
POD                      Detail records table
PD_PHNO              fk
PD_ITEM
PD_QTY
PD_PRICE
PD_LOCAL_AMT        
PD_FOREIGN_AMT
M_PD_FOREIGN_AMT       Formula (PD_QTY * PD_PRICE)
M_PD_LOCAL_AMT           Formula (M_PD_FOREIGN_AMT/PH_FXRATE)
CTRL                 Control block
M_PH_PD_LOCAL_TOT           Summary-Sum-Table=POD, Field=M_PD_LOCAL_AMT
M_PH_PD_FOREIGN_TOT       Summary-Sum-Table=POD, Field=M_PD_FOREIGN_AMT
Triggers
POH Table
Pre-Insert   and   Pre-Update
:PH_PD_LOCAL_TOT := :M_PH_PD_LOCAL_TOT
:PH_PD_FOREIGN_TOT  := :M_PH_PD_FOREIGN_TOT
POD Table
Pre-Insert   and   Pre-Update
:PD_LOCAL_AMT := :M_PD_FOREIGN_AMT
:PD_FOREIGN_AMT :=  :M_PD_LOCAL_AMTThe problem that i am facing is while i UPDATE a record.
whats happening is when the form is in Query mode and if i change a record, lets say
change the value of the field PH_FXRATE, then what happens is, on screen i get all Detail
record's M_PD_LOCAL_AMT Calculated & Updated, but the actual db field PD_LOCAL_AMT remains unchanged
in the database after i press F10 or Save button.
The update takes place for the POH table and form displays 1 Record updated.
whereas if i have for example 4 detail records, then form should update those as well and display finally
5 records updated is'nt it..?
In query mode,if i insert new or modify an existing record in the detail block, then at this point, form marks just
that particular record as CHANGED. Thus making changes at db level only for this particular record.
what i want is once i make changes to the field PH_FXRATE, then form should mark all detail records
as CHANGED and on saving, the PRE-UPDATE tigger of POD table should come in to force and the changes
in the values of M_PD_LOCAL_AMT in turn to the db field PD_LOCAL_AMT should get affected at db level.
i have also tried to put these assignments
:PD_LOCAL_AMT := :M_PD_FOREIGN_AMT
:PD_FOREIGN_AMT := :M_PD_LOCAL_AMT
at PRE-UPDATE of POH table, thinking that form might consider
all detail records, at this point. i noticed that it does it, but only picks
1 record (i guess just the first record always) and change a db level.
No. 2 Issue:
i have put a POST-FORM-COMMIT at form level for auditing the Total fields of POH table against the details records.
Declare
     M_LC_AMOUNT NUMBER(13,3);
              M_FC_AMOUNT NUMBER(13,3);
Begin
     SELECT SUM(PD_LOCAL_AMT) INTO M_LC_AMOUNT
     FROM POD
     WHERE  PD_PHNO = :PD_PHNO;
     IF  :PH_PD_LOCAL_TOT != M_LC_AMOUNT  THEN
          :PH_PD_LOCAL_TOT := M_LC_AMOUNT;
     END IF;
     SELECT SUM(PD_LOCAL_AMT) INTO M_FC_AMOUNT
     FROM    POD
     WHERE  PD_PHNO = :PD_PHNO;
     IF  :PH_PD_FOREIGN_TOT != M_FC_AMOUNT  THEN
          :PH_PD_FOREIGN_TOT := M_FC_AMOUNT;
     END IF;
End;i was testing and notice that in a query mode when all records are displayed.
if i go on changing values on records and save or save later keeping the form open,
form allows, but if 1 come back to a record which i may have changed and saved earlier, then it flashes Error;
"Records has been changed by another user, requery to ..."
i want to do an Audit before final db-Commit and keep the user free from this Error..
Please tell me first of all, is my approach for both of my issues,correct.?
if not, then please suggest what should be changed.
i'll highly appreciate for all your help. TYVM. Regards.

Answer 1

I did exactly as you suggested. It works well for new record insertion
but when i press F7 to query it, its flashes messages before displaying detail records
Field must be entered.
Mr. Andreas,
i have problem only when i change value of PH_FXRATE. It re-calculates on screen values for M_PD_LOCAL_AMT
(Formula M_PD_FOREIGN_AMT/PH_FXRATE)
i want the changed value of M_PD_LOCAL_AMT to be saved in the actual db-field PD_LOCAL_AMT.
for this i have PRE-UPDATE on POD Table
:PD_LOCAL_AMT := :M_PD_LOCAL_AMT
:PD_FOREIGN_AMT := :M_PD_FOREIGN_AMT
Which is doing that.It is not marking the detial record as CHANGED.
I tried giving the above assignments in the PRE-UPDATE on POH table.
It saves the changed value in the db-field, but not all detail records, if more than 1.
what you have suggested, will get me acheived what i am looking for..?