Use checkbox to fill grades

[giol]

Hi, i am working on a database that will allow me and my colleagues to manage our student's grades
I have created all the basic tables that include student and teacher data. I also created a table with the subjects (yes/no type) that are being graded and the weight of each subject (basically how many points to add to the final grade if the subject checkbox is checked)


I have created a form (frmgradebook) where after selecting from dropdown lists the student data, date, lesson, etc, i have a list of the subjects to be graded with checkboxes next to them. I want to calculate the total grade by multiplying the value of the checkbox with the weight of the subject associated with the checkbox's subject. The only way i can do it so far is to build and expression that multiplies each checkbox value with the corresponding weight and sums it. The problem with this is that if another teacher wants to change the weight of a subject he will need to change the expression and that is not very friendly.
How can i build an expression that multiplies the checkbox value (-1 or 0) with the weight value that is recorded in a table with all the subjects?
Thank you.

[ranman256]

No , you wouldnt change the expression...the query would have a calculated field...your checkbox here I called [ToBGraded]:

sum(abs([ToBGraded]) * [Weight]) as WtVal

[giol]

I am not sure i understand it. Please explain where to add the calculated field on the following example.
Lets say i have two subjects to be graded for the lesson.
Subject1 with a weight of 5
Subject2 with a weight of 10
So i have a tbl with two columns (tblSubjects) : subject name | weight
and the form(frmGrade) with the following
subject1 [] (checkbox)
subject2 [] (checkbox)
final grade ____
If both check boxes are true the final grade should be 15.