Project Database

Project Database

I have two requests please.

We have created a Projects database which has a number of subforms, one of which is comments. It has three fields - Date, Who, Comment

Elsewhere on the Main Form there is a comments field from an earlier version. I would like to move these comments to the subform and then delete the original comments field.

Is there some code that would achieve that please, or do I export and re import. Any advice appreciated.

The second request relates to managing Project value. On the main form I have a Value field. I also have an invoice subform which records Invoice Number, Date of Invoice, Invoice Value. I would like to have a running diminishing total - for example

Main form invoice value - $10,000.00
Inv 22 - 26 April 2016 - $3200.00 Balance - $6800.00
Inv 34 - 26 May 2016 - $985.00 Balance - $5815.00
Inv 57 - 26 June 2016 - $4700.00 Balance - $1115.00

Etc

I assume that once the various amounts are entered into the subform and saved, then this information “disappears” from a form but is shown in the relevant report.

Any advice would be appreciated 
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UPDATE
The first question has been resolved - there were only a small number of entries

Question 2 I have prepared this script where PROJECT is the sub form
Project
    (
        displayname  =  "Project Approvals"
        type  =  grid
        values  =  Project_Sub_Form.ID
        Contractor
        (
            on user input
            {
                grandTotal = 0.0;
                for each Contractor in Project
                {
                    if (Project.Value  !=  null)
                    {
                        grandTotal = (grandTotal  +  Project.Value);
                    }
                    input.Sub_Total = grandTotal;
                }
            }
        )
    )

    Sub_Total
    (
        displayname  =  "Sub Total"
        type  =  NZD
        width  =  200px
    )

In part this works. When I enter a value in the first line - say 10, the Sub_Total field also populates as 10
When I enter another value in the new row say 12, I was expecting Sub_total to increase to 22. But instead it become 20. And likewise with a third row say 5 expecting the Sub_Total to become 27, it becomes 30.

So there is something wrong with my script as it appears to multiply the first value entered by the number of rows.
 I should explain the fields in the sub form are:
Date Awarded
Value
Contractor
Contact
Mobile
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