Managing the Relationship Graph with Squids
I recently received an email asking, "How the heck do I name my table occurrences so that they make sense?". This is a very common question, so I figured I would publish the answer here.
When you built your first database in FileMaker 8, you probably created what is often referred to as a "Spider Graph" (Figure 1). If so, I am guessing that you found that Spider Graphs are very difficult to manage. This is especially apparent when attempting to select the correct TO from a popup menu, say, when specifying a TO for a new layout or portal.
Figure 1. The dreaded Spider Graph
The Problem
The trouble stems from the fact that in 8, we name the nodes (Table Occurrences), whereas in 6, we name the edges (the relationships themselves). To complicate matters, in 8 the relationships are bi-directional and can be many levels deep, so naming the TO from the perspective of another TO on a Spider Graph may makes no sense if the perspective changes.
For example, let's say you have 3 TOs named and related like so:
Company --< Employment From Company >-- Person
If you make a layout based on Company and put a portal on that layout based on Employment From Company, everything is fine. However, if you make a layout based on Person and put a portal on that layout based on Employment From Company, the name "Employment From Company" makes no sense.
The point I am trying to make is that you should shy away from naming TOs based on perspective in a Spider Graph. In fact, you should shy away from Spider Graphs altogether.
The Solution
I use Squids to solve the Spider problem. It is similar to something you may have heard referred to as Table Occurrence Groups (TOGs), but it is not the same thing.
BTW - The name "Squids" popped into my head because when you zoom way out in the graph, it looks like a bunch of squids in there. Download the sample file at the end of this article to see if you agree (Figure 2). Plus, it makes me laugh.
Figure 2. Squids to the rescue!
The concept is to create little disconnected groups of TOs in the graph. Each group has a root TO (the "squid head") and strings of related TOs (the "squid legs"). The TOs are named from the perspective of the squid head like so:
Company --< Company to Employment >-- Company to Employment to Person
In this example, "Company" is based on the Company table, "Company to Employment" is based on the Employment table and "Company to Employment to Person" is based on the Person table.
It is akin to a file path, but with the word "to" in place of "/". I setted on the word "to" as the delimiter after discarding a number of other options, most notibly the period character (".") and the pipe character ("|"). Periods are no good because they will muck up the works if you ever attempt ODBC access. And as for the pipe, I just find it tough read - plus it is hard to distinguish from capital letter "I" and lowercase "l" (see what I mean?).
Following this naming convention makes selecting a TO from a popup menu dead simple (Figure 3). The names can get a bit long, but that has yet to present a problem for me. If you must, come up with standard abbreviations for your table names but try to be 100% consistant or you will regret it when it comes time to do your scripting.
Figure 3. The Squid Pop-Up Menu
The Rules
There are only a few rules to "Squidding", but they must be followed religiously for the methodology to work for you.
The ALWAYS Rules of Squidding:
- ALWAYS base your layouts on squid heads
- ALWAYS base your calculations on squid heads (i.e. "Evaluate this calculation from the context of <squid head>")
- ALWAYS start your related value lists from squid heads (i.e. "Include related values starting from <squid head>")
- ALWAYS base your portals on a TO from a squid leg
Sometime you may find it difficult to follow these rules religiously. In cases like this, it is probable that you are trying to solve a problem by "Graphing" rather than "Scripting". That is to say, you are probably doing something in the graph that you should really do with a script. This is a pretty subjective opinion that I intend to support with another article soon. For now, just follow the rules and I think you will be happy in the long run.
Conclusion
Do yourself a favor and spend a little time to get your head around Squids. I think that you will find that once you get the hang of squidding, you will never want to see another Spider Graph.
