How do I set up a calculated column to reference itself?

Question

I need to set up a column that will keep a running total of values. I have a program that automatically sets values for the columns in SharePoint. The program will overwrite the previous value within that column and I need a way of keeping a total from the previous and most up to date values.

I was thinking of setting up a calculated column that sums itself with the value of the updated column.

Is this possible with a calculated column? Would a workflow give me the capabilites I need?

Answer 1

As James has indicated, the calculated column can only work on data that currently exists in the current row, so the running total can't be done by a calculated column.

However, if I'm understanding you correctly, you could do this with two fields: - Field A - the field that your external program updates - default value of 0 - Field B - the field with the running total - default value of 0

Then you add an event receiver to the list. Any time an item in the list is created, you assign whatever is in Field A to Field B. I.e. B = A; Additionally, whenever an item in the list is updated, your event receiver can update the value of B. I.e., B = B + A;

You will want to be careful, because if a user has access to edit an item, they could edit Field B and screw up your totals.

Answer 2

The formula and idea you had will generate an infinite loop.

"total of values fed in automatically from an xml" - how do you mean?

The calculate column on works on data only from the current row.