Calculating Course cost per student My Scenario:
One admin user is entering these information.
I have 3 content types: student, register, course.
Student is obvious, i.e. student_number, personal_info, etc
Course contains: course_name &amp; course_costs, etc.
Register contains: ref to course, course_date, ref to students who attend this course.

My question: How would I go about calculating/working out costs per student, per course?

Do I need to use rules? I assume commerce is out of the picture, as one admin user is entering this information. Any direction would help. Thank you.
Is this value stored on the Register Content Type?

You can use the computed_field module.

You will need to read every value in ref_to_course field. Load each of those nodes. From there, read the course_cost and add the values.

Then store the values on the computed field.



Another option is using views module. You can attach a View to the content type. The view can then use the node NID, read the ref_to_course. Add relationship, read the course_cost and add those.



I think the first might be better since you calculate it once.