Creating and Using Custom Functions
This is an advanced topic intended for programmers.
Stonefield Query can use "custom" functions in various places, such as report fields. A custom function is code that does something when it's called. Custom functions allow you to do just about anything you wish, including:
Create complex formulas and display the results in a report.
Ask the user for a value and use that value in the report.
There are a couple of ways you can create custom functions:
Create a text file called REPPROCS.PRG in the directory where Stonefield Query's data files are stored. Edit this file using any text editor (not a word processor, such as Microsoft Word, which stores binary files, but an editor such as Notepad that stores text files). This file can contain as many functions as you wish. Each function should start with "FUNCTION" followed by the function name and any parameters (in parentheses), and end with "RETURN" or "RETURN variable or expression."
Create a text file called FunctionName.PRG in the Functions subdirectory of the folder where Stonefield Query's data files are stored, where FunctionName is the name of the function. Edit this file using any text editor such as Notepad. Unlike REPPROCS.PRG, this file can only contain a single function and should not include a "FUNCTION" statement. It can, however, include an LPARAMETERS statement if it accepts any parameters and should end with "RETURN" or "RETURN variable or expression."
Here's an example of a UDF. This function determines the commission for a sale based on a complex formula: if the sale amount is over $1,000, the commission is 12%; between $500 and $1,000, it's 10%; between $100 and $500, it's 8%; and there's no commission for sales less than $100.
function CalculateCommission(SaleAmount) do case case SaleAmount >= 1000 Commission = SaleAmount * 0.12 case SaleAmount >= 500 and SaleAmount < 1000 Commission = SaleAmount * 0.10 case SaleAmount >= 100 and SaleAmount < 500 Commission = SaleAmount * 0.08 otherwise Commission = 0 endcase return Commission
To use this UDF in a commission report, create a new report and add the desired fields, including the sale amount field. Then, turn on the Advanced layout option and click Edit to bring up the Advanced Report Designer. Create a new field and enter the following for the field's expression:
ARITRS.NSALESAMT is the name of the field in this example that contains the sale amount. Alternately, instead of having to type the field name, you can click the Expression Builder button, type "CalculateCommission(", select the AR Invoice Line Items table, double-click the Subtotal Amount field to add it to the expression, then type a closing ")".
Enter 999,999.99 for the Format and then click OK. To create a subtotal of commissions by user, copy the field and paste it, then move the copy to the group footer. Double-click the copy, select the Calculate page, and choose Sum from the Calculation type option. Save and run the report.
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