I'm working on a software tracking DB that will contain license keys, etc. for our company. I know this is probably a newbie question, but I'm running into a hitch with decrementing the total quantity of licenses available by "1" when a user is assigned a license. I'm using a portal to show related data from a Software Users table in the Licensing Tracking record (it's own table). I'd like to be able to assign the software key to a user and have the "Licenses Available" field show the number that remain available. I've tried some basic calculations/scripting, to no avail.
If any of you have any suggestions, that would be much appreciated.
Attached is what the two related tables look like.