table field update by method field form

i am new on the development.

How i can update the table field?

I create one field on the table.Also create methods for calculation.

Then add one field in the forms.
Call that datamethod on that field.
So in the form this method works fine.Show the netweight.

But what I have to do to update the table field,because I cannot update the table field it is empty.

Why would you save the result of the display method to database? You would have to update it every time when any of the underlying field changes, which would be more work for you as a developer and also for the system. Usually it’s better to keep the table normalized.

So is there any better way to save the result in the field?

i want to save the netweight on the database field and netweight is being calcalute base on two quantites.

My question was why to save it at all, if it can be easily calculated and saving the calculated value would require additional maintenance.

So you mean to say that i will not save the value on the table field, instead i can show on the report format.

Just for my information which kind of additional maintenance are we talking about.

Please read my first reply once more, I explained it there.