Different function

Hello All

I would like to suggest a different function to PC SOFT to be available in Version 14.
This function returns the difference between the current and the previous value of an expression.
The one's that I miss from my old 4GL function...

syntax:
Result = DifferentValue(expression)

Use:
the different function subtracts the old value from the new value and returns
the different

To illustrate:
this function operates differently depending on the operating mode:

Add mode
the old value of expression is always zero, so the result is the new value.
DifferentValue = new - 0
12 = 12 - 0

Modify mode
the old value is substracted from the new, this is where it is really usefull.
DifferentValue = new - old
2 = 12 - 10 or
-4 = 6 - 10

Delete mode
the new value of expression is always zero, the result is substracted from
zero, giving the negative of the old value.
DifferentValue = 0 - old
-10 = 0 - 10

In code...

// Add mode //     
            mst_stock.quantity_on_hand -= dtl_sales.quantity
            hadd(dtl_sales)

             or...

            mst_stock.quantity_on_hand -= DifferentValue(dtl_sales.quantity)
            hadd(dtl_sales)

// Modify mode //
            mst_stock.quantity_on_hand -= DifferentValue(dtl_sales.quantity)
            hmodify(dtl_sales)


// Delete mode // 
            mst_stock.quantity_on_hand -= DifferentValue(dtl_sales.quantity)
            hdelete(dtl_sales)

This function is really usefull when files update operations on procedure/ trigger

Regards
Toddy




Edited 1 time(s). Last edit at 11/23/2008 10:05AM by Toddy Utomo.