My database currently stores fairly basic work order information for a stone company that fabricates marble and granite countertops, fireplaces, etc. The primary purpose actually relates to "slab control" or inventory. Anyway, the current entry for quantity used is direct input (with shop ticket in front of me and calculator in hand). It then does some simple math with quantity sold, etc.
I'd like the quantity used to be based on the slab sizes because that's what gets recorded on the shop ticket. I envisioned a subtable that records width and height of each slab (obviously number of slabs varies). Then I'd somehow get the total sq footage from that and plug it into my existing math. I'm not getting anywhere fast and I can't seem to find an example database that relevant.
This is my first real database of any consequence, using it as a guinea pig so you'll find a few other unclean things in there. But it's small enough that figuring it out should be pretty easy. Any help would be much appreciated.