Order of creation is important with calcs/lookups

[richardb]

Was working through the audit trail solution in the book Advanced FileMaker Pro 5.5 by Bowers and Moyer. As some of you have noted in previous posts, if you follow the book it doesn't work but it does on the supplied CD file. The problem is that in the book (pg.88), the authors say that calculations will trigger before lookups, allowing time for a calculation (Audit_Current Text) to capture both the old and new values in the field. But it doesn't work if you constuct the fields as they suggest in the book as the capturing calculation is created AFTER the lookup has been created - hence only the new value is captured. If you go to the CD file which does work and in Define Fields order by creation, you will notice that the Audit_Current Text field is the first one created and hence will capture the old and new changes before the lookups. It is the order of creation and not the concept of calculations triggering before lookups that seems to hold true here. Perhaps the book could have emphasized this point and saved me (and I suspect a few of you) several hours of deep contemplation (garnished with a bit of frustration).

I post this to hopefully save someone else some time nutting it out.