29 Mar 2019: Demo file has been updated to v2. See comments for details.
Editor’s note: Geoff Gerhard of Creative Solutions is one of those “quiet” developers who has been helpfully sharing his knowledge in online FileMaker forums for more than 20 years. I personally have benefited enormously from his expertise, and am pleased to feature his first appearance as a guest author here on FileMaker Hacks.
Demo file: BillOfMaterialsDemo-v2.zip
Today I want to talk about a potential problem lurking in a small percentage of FileMaker solutions, and discuss various options for mitigating it.
As you may know, there are three ways to display a new window…
…and it’s this last option that can, depending on circumstances, be problematical.
I say “depending on circumstances” because typically it’s okay for a user to spawn a new window, which is to say that doing so doesn’t pose any challenges beyond those the developer already faces when building a multi-user system, which presumably the developer has considered and has intelligently dealt with.
Editor’s note: I first became aware of Paul Jansen when I licensed his FMTools in the late 1990s, and I finally had the pleasure of meeting him last June at dotFMP after 20 years of online and voice communication. It’s an honor and a privilege to welcome him to FileMaker Hacks as a guest author.
FileMaker is pretty flexible. As developers we are given options as to how to reference things; fields, scripts and layouts can be referenced by name or number/id. Whilst we know that referencing things by name is more fragile, it is still a very useful capability to have, but it is definitely more robust to reference by ID…
As windows are probably the most likely things to have their names changed during normal day to day usage of a FileMaker Database it would be really useful if we could keep track of them by an ID independent of the displayed window title. Another benefit of having access to an ID to identify a window is that we then have to option to very easily store and access window specific variables. Kevin has made use of window specific variables based upon the window name in several articles and I suggest that access to a numeric ID that was independent of the window title would be an improvement. Continue reading “Creating and Using Invisible Window IDs”
It’s been a few years since we last had a tips ‘n’ tricks article here at FileMaker Hacks, and during the interim some new items have accumulated in the old developer bag of tricks. (If you like this sort of thing, you may also want to check out part 1 and part 2.) Some of these are obscure, and one is very basic. Ideally developers at all levels of expertise will find something useful (or worth arguing about) in what follows.
I recall Corn Walker introducing a DevCon session by saying, “I’m just a kid who paid attention in math class.” Along similar lines I pay attention when smart people share their hard-won wisdom, and a number of the following tips come from these individuals with (what I hope is) proper attribution.
Some FileMaker functions require one or more arguments, e.g., Sum () or Evaluate ()… some do not require an argument, e.g., Random… and there is a single function where the argument is optional, i.e., the function can stand alone without parentheses like so…
Function
…or with parentheses like so:
Function ( argument )
Do you know which one it is? (See further discussion at the end of this article.) Continue reading “Tips ’n’ Tricks, part 3”
Recently we’ve looked at two methods to generate a “faux” subsummary to address a shortcoming of FileMaker native subsummaries… namely that in a multipage report you can have orphaned entries at the top of a given page with no indication of what parent entity they belong to.
The methods were documented here:
One limitation of both the above approaches is that they only worked with fixed-height report rows. Well today we have a nice, outside the box solution from Daniel Wood that does not suffer from this limitation.
Demo file: Faux-Subsummaries-with-Variable-Height-Rows.zip (requires FM 16 or later) Continue reading “Faux Subsummaries with Variable Height Rows”
Today we’re going to take another look at a challenge we discussed last time (in Conditional Summary Report Header)… namely how to cajole FileMaker into displaying a subsummary, or a reasonable facsimile thereof, at the top of a report page when items in the group begin on an earlier page.
Demo file: Faux Subsummaries via JSON + Virtual List
Continue reading “Faux Subsummaries via JSON + Virtual List”
This a quick followup to last month’s part 2, because today I want to to dig a little deeper into JSONSetElement and take a closer look at the first argument:
As I wrote last time…
Part of what makes JSONSetElement so powerful is that it can be used both to create new entries, and to update existing entries. Specify a valid address, and it will either create the entry if it doesn’t already exist, or update it if it does.
Let’s talk about the update aspect first, because it’s extremely straight forward. If you have existing JSON in a variable, for example $$simpleJSON, you can update it (i.e., add new elements or change existing elements) like so:
In other words, you use your existing JSON as the first argument.
But when it comes to creating new JSON, there are three possible first arguments to consider.
At the risk of stating the obvious, in the first two cases we are being explicit, but in the third case we are not. (Note: If you’re unclear on the distinction between objects and arrays, this was covered in great detail in part 1.)
This is a follow up to Thinking About JSON, part 1. Last time we were primarily concerned with learning about JSON paths and structures, and reading JSON. This time around we’re going to look at creating and manipulating JSON.
Demo file: winery-json.zip
(If the above screen shot looks familiar you have a good memory, because today’s demo is based on the one that accompanied this article: Summary List Fields in FM 13.)
To briefly recap, JSON is built on two structures…
…and where things get interesting is that the “values” in either of the above structures can themselves be JSON (i.e., an object or an array). This defining feature of JSON, whereby a JSON structure can, and frequently does, contain embedded smaller JSON structures, was explored in detail in part 1, and we will see some examples of this today as well. Continue reading “Thinking About JSON, part 2”
Acknowledgment: As always a huge thank you to Bruce Robertson, for inventing virtual list, and for many other contributions to the FM community over the years.
As a follow up to my recent “Virtual List on Steroids” presentations at DIG-FM and dotFMP, today I want to take a fresh look at using JSON arrays in conjunction with Virtual List Reporting.
JSON arrays + Virtual List are a natural fit, but, as we shall see, small changes in methodology can make a huge difference in terms of performance, and the approaches we’re going to explore today are the result of a lot of trial and error, and incorporate feedback and suggestions from Dave Graham, Paul Jansen and Perren Smith.
What follows will assume the reader is somewhat familiar with the basic ideas behind Virtual List. If you aren’t familiar, or need a refresher, you can find references to earlier articles here: Virtual List on Steroids, part 2. We’ll get to the demos in just a minute, but first, a review of some of the benefits of using virtual list.
Here’s the main idea in a nutshell:
