Auto-Reducing Value Lists (Revisited)
You can't be in more than one place at a time - unless you're using a database that's improperly configured. When considering a meeting at a fixed time, you can only have employees assigned to that meeting once. At least that's how it should be.
Whether we're talking about meetings, or any other situation where you want to limit how many times a value can be selected, it's knowing how to create an Inverse Value List that allows you to automatically reduce the options to choose from. This video will show you how to control which values are possible when working in FileMaker Pro 7.
Update (8/15/08) FileMaker has updated the way relationships work in later versions of FileMaker. Not equals relationships, which this technique uses, will not reveal results within a portal when one side of the relationship is either NULL or empty(blank). This means you at least need some value on both sides. Since this technique uses record serial values, all you have to do is provide a 0 [zero] to make the not equals operator on the relationship to work.
Comments
Auto-reducing value lists
Hi Matt:
I started using this technique in FM 7 and it works properly. The problem came when I tried to implement it in FM8 or later versions. In the second technique, when you delete (uncheck) all selections in the second portal, all rows dessapear in the first portal (where you choose from) and there is no way to populate it again.
It would be nice if you revisit this technique and explain us how to resolve this bug.
thanks in advance:
Maria Ridao
I can confirm that bug. A
I can confirm that bug. A review would be very nice! Im using FM9 Advanced.
I updated the files
Looks like I'm pretty slow on some of these types of things. Probably because I already understood what to do. The solution in this technique is the most basic of all. All you have to do is add a 0 [zero] to the calculated key used in the not equals relationship.
Hope this helps out. It's a great technique!
-- Matt Petrowsky - ISO FileMaker Magazine Editor