I have a simple table (DURATION) which has a field to store duration in minutes,
let us call it DURATION_MINUTES

To make it more "user friendly" then I make a view which split the
DURATION_MINUTES in 2 integer fields: DUR_HOUR, DUR_MIN by simple math:

Hour = Total_Minutes/60
Minute = Total_Minutes - ((Total_Minutes/60)*60)

Note: integer division results in integer.

To make it updatable, I make the trigger for the view which calculate
back the DUR_HOUR and DUR_MIN to its underlying field
DURATION_MINUTES. It is also a simple math:

Total_Minutes = Hour*60 + Minutes

Displaying the view's data runs great. However, updating the view is
odd, the values stored to field DURATION_MINUTES in the underlying
table are the DUR_HOUR values (decreasing by 60 factor).

Do I miss something obvious here?

Below is the script to reproduce the symptom.

== 8< The DDL =====
CREATE DATABASE 'JUST_TEST.FDB' user 'SYSDBA' password 'masterkey';
CREATE TABLE DURATION ( ID integer, DURATION_MINUTES integer);

CREATE VIEW VIEW_DUR ( ID,DUR_HOUR,DUR_MIN)
as SELECT ID,
cast( DURATION_MINUTES/60 as INTEGER),
cast( DURATION_MINUTES - ((DURATION_MINUTES/60)*60) as integer)
from DURATION;

SET TERM ^ ;
CREATE TRIGGER UPDATE_VIEW_DUR FOR VIEW_DUR ACTIVE
BEFORE INSERT OR UPDATE OR DELETE POSITION 0
AS
BEGIN
if (INSERTING) then begin
INSERT INTO DURATION (ID,DURATION_MINUTES)
values (NEW.ID,NEW.DUR_HOUR*60+NEW.DUR_MIN);
end

if (UPDATING) then begin
UPDATE DURATION
set ID=NEW.ID,
DURATION_MINUTES=NEW.DUR_HOUR*60+NEW.DUR_MIN
where ID=OLD.ID;
end

if (DELETING) then begin
DELETE from DURATION where ID=OLD.ID;
end

END^
SET TERM ; ^

COMMIT;
== 8< =====

--Populate record
INSERT INTO DURATION (ID,DURATION_MINUTES) VALUES (1,960);
COMMIT;


--Query is okay
SELECT * FROM VIEW_DUR;
SQL> SELECT * FROM VIEW_DUR;

ID DUR_HOUR DUR_MIN
============ ============ ============

1 16 0

--Just try to update with it self and see what's happend
SQL> update VIEW_DUR set ID=ID;
SQL> commit;
SQL> SELECT * FROM VIEW_DUR;

ID DUR_HOUR DUR_MIN
============ ============ ============

1 0 16

Very strange!

Can somebody enlighten me? I am using FB 1.5.3 on Win2000 SP4.

TIA,

--
Bambang P.