Today was the first test of the new AdaptiveDB code rewrites and new features on a serious scale, on the MoM db. Greg and I ported it over by writing a new local_classes.php file for the system. These are some notable issues, all solved:

• I had forgotten that I'd created a special lat-long field for storing coordinates, for the MoM project. We had to port that field definition back into the main codebase.
• That field wasn't quite functioning right, because when an empty string was returned to the db for storage, a zero was written. Obviously zero is a real coordinate, which is not the same as no coordinate at all. So I've rewritten the saveToDb() code in MdhRecord to take account of that.
• We discovered that when an integer field is used as a filter, a zero is written to the filter input automatically because zero was being set as the default value for the field, causing a filter value to be created on the page without the user's intervention. Because integer fields CAN be legitimately zero, we can't of course treat this as a special case, so I had to depend on the typing looseness of PHP to set the initial value of the field to an empty string, which solves the problem.
• Various other minor tweaks.

The idea of presenting data from a link table as if it were "part of" two different parent tables works really well; you just have to remember to get the field name parameters right (which is pretty hard -- I'm going to have to do some proper documentation here, once it all shakes down).