Setting up and navigating hierarchical trees

[mikedr]

I think I'm constructing a Rube Goldberg-esque solution to my problem.  Here's the application domain.  I have a table of records that correspond to patent applications, which are commonly referred to as matters.  A matter can claim (but does not have to) immediate priority to one and only one other matter.  However, more than one matter can claim priority to the same matter, and a matter that has matter(s) which claim priority to it can itself claim priority to a matter.  When a matter claims priority to another matter, this means that the former matter is of lower priority than the latter matter.

 

I realize this is confusing, so here's a concrete example that I've been using for testing purposes.  Say there are seven matters A, B, C, D, E, F, G.  B and C claim priority to A, and are thus of lower priority than A.  D and E claim priority to B, and are thus of lower priority than B and A.  F and G claim priority to E, and are thus of lower priority than E, B, and A.

 

For what it's worth, I created another table called priority, which lists two matters, the matter claiming priority, and the matter to which it claims priority.  So, in the example, there are six records in this new table, one for each priority relationship.  In hindsight, this is perhaps not needed, since in my main matter table, I could simply have a matter refer to another matter to which it claims priority.

 

Now, the problem.  Per the concrete example listed above, the result of matters claiming priority to other matters effectively results in a hierarchical tree.  I want to list all the matters that are in the same tree -- that is, all the matters in any priority chain.  So, regardless if I start at matter A, B, C, D, E, F, or G, I end up with the same list of matters.

 

Here's how I've done this.  I have a first script that finds the highest priority matter in the tree.  So, if you started at A, you're OK, because A is the highest priority.  But if you start from E, say, it would find B as being of higher priority, and then finally find A as being of highest priority.  That is, regardless of whether you start at A, B, C, D, E, F, or G, you always end up at A.

 

Then, this script calls a second script that recursively calls itself.  The second script has a parameter that is a current matter.  It locates any matters that claim priority to the current matter.  If there are any such matters, for each of these matters the script calls itself again, to determine whether there are any matters that claim priority to these matters.  This recursion continues until it locates all matters that do not have any other matter claiming priority to them.

 

This indeed works as expected.  Once we get to A in the first script, the call to the second script passing A finds B and C.  For each of B and C, the second script calls itself.  When the second script is operating on B as the current matter, it finds D and E, and when operating on E as the current matter, it finds F and G.

 

What I don't like about this approach is that there is a *LOT* of searching going on.  But it does work. 

 

The idea is that once I get all the matters in a family -- i.e., all of A, B, C, D, E, F, and G -- I can list these applications in a layout, and long-term, call some (external) tree building tool appropriately to create a visual representation.

 

Critically, though, a user is just going to specify at most one priority relationship for any given matter, that the given matter claims priority to (and thus is of lower priority than) another matter.  From these priority relationships, then, I need to figure out the family of matters.