FileMaker Pro 9: The Missing Manual

Chapter 11. Advanced Calculations

In the previous two chapters, you learned loads of ways calculations can make your databases work harder for you. But the functions you’ve learned so far can’t make your databases work much smarter. For example, what if you want to add a five-percent delinquency charge to invoices over a month old? You could do it in any number of ways, from sorting invoice records to creating a special “past due balance” field. But they all either make extra work for the person using the database, or give you yet another field to worry about every time you tweak, troubleshoot, or repurpose the database. The most elegant solution is to let the database figure out for itself when an invoice is past due. In other words, you want to create a calculation that makes a decision based on current data, whatever it may be. This chapter shows you how to give your calculations that brainpower by using logical functions and other advanced techniques.

Note

Before you read on, now’s a good time to download a fresh copy of the working database. This chapter refers to some layouts and fields that your copy may not have. download a copy of this chapter’s sample file at www.missingmanuals.com/cds..