Disclaimer: This article contains speculative and experimental techniques that are in the proof-of-concept stage. Use at your own risk and test thoroughly.

FYI: In March at the Portland PauseOnError un-conference, Matt Navarre and I had a freewheeling Separation Model discussion, a podcast of which has just been posted as episode 85 at FileMaker Talk.

Welcome to the fourth and final installment in our series on Radical Separation. Today’s article assumes familiarity with part 1, part 2 & part 3, and continues in the direction we were headed at the end of part 3. Specifically, we will finish up our exploration of “virtual calculations” by examing an intriguing approach suggested by Barry Isakson to a) reduce the field count, b) solve the “define more fields than you’ll ever need” problem, and c) accommodate summary fields, and I invite you to follow along in today’s demo file, Virtual Calculations, Part 4, if you are so inclined.

Disclaimer: This article contains speculative and experimental techniques that are in the proof-of-concept stage. Use at your own risk and test thoroughly.

Today we’re going to delve further into the concept of virtual calculations, picking up where we left off last time, and with the assumption that readers are familiar with the material in part 1 and part 2 . We’ll look at some ways to make this technique less brittle (prone to breakage if objects are renamed), and also less opaque to DDR analysis tools such as BaseElements and Inspector. We’ll also see if the technique can be applied to auto-enter calc fields, and finally, we’ll explore some ways to make the technique easier to implement.

Demo Files:

Disclaimer: This article contains speculative and experimental techniques that are in the proof-of-concept stage. Use at your own risk and test thoroughly.

In part 1 of this series, we defined radical separation as a separation model scenario in which the developer no longer has access to a data file once a solution had been deployed. Updates to the solution are delivered in the standard separation model manner: by swapping in a new interface file.

We explored the concept of “virtual calculations”, where certain (unstored) calculated fields in a data file derive their definitions from syntax stored as data in a special table in the interface file. The advantage of this being that calculation logic can be redefined programatically by the simple expedient of replacing the interface file.

In the six weeks that have gone by since I posted part 1, I have made a couple improvements to the technique, one of which which we’ll examine in today’s demo file: Virtual Calcs, Part 2