IMHO, using a general database program for genealogy is like cutting down a wrecked pickup truck to make a trailer; you can do it, but it will be awkward.
I see messages all the time about converting Excel files or Access databases to GEDCOM files, presumably from people who kept their data that way and now want to go to a real genealogy program.
I may be seeing a skewed sample of the population, and you may have considered this already; if so, please forgive me. If you are an accomplished Database Designer, you may want to design one just for genealogy for fun. However - have you considered getting Roots Magic (FOW's successor) or FTM for the PC and Reunion for the MAC, then sharing your files via GEDCOM?
If the genealogy programs you get can write GEDCOMs for selected individuals, as opposed to all individuals (most can), you'd be set; you could share data and you'd have a program designed for genealogy, with all the features you needed. You could then spend less time fussing with data base design and more time poring over faint census images, obits and old wills.