The deeper we get in sub inventory, the more we keep having to go back and forth to figure out the part category. Basically, all sub attributes are based off of the part category. Maybe we should hold and store that data per line item vs having to look it up every time. It does duplicate data (for storage), but it would really speed things up. If needed, we could add a special watcher, in case the part category every changed, to help cascade all part category id updates, but at least we wouldn't have to keep looking it up. That seems to be a pain.

Long story made short... add the part_category_id column to the time_sub_inventory_[53] table. Make sure and cascade all entries (forwards and backwards), but that would really help with looking things back up. Faster on searches and less table linking needed.

Another note, along similar channels, sometimes getting to the actual sub attribute values (actual data, not the columns themselves, but the stored data) is sometimes really hard to pull back. Everything is related and multiple levels deep. Maybe look into that and seeing if there are easier ways of getting the information back. That could be more database columns and/or some other kind of flag that helps us look things up quicker. We are currently able to store the data pretty efficiently, but getting it back out is a pain in the rear. help this process out by looking at the common look-up options. If needed, it is totally ok to duplicate data to  speed up the look-ups. We just monitor things and make sure and cascade changes if and when a change is made.