Read / Write to ShopSite Database (newbie)

[Eddie Caplan]

I'm a ShopSite newbie. We have built a website that has its own
customer login information and database. I'd like to somehow integrate
that with ShopSite's database of Customer Registration, Orders,
Shipping and Billing information.

That way, the customer could log into our site once, and be "logged in"
for both ShopSite and for the rest of the website.

1. Possible?

2. Is there ANYTHING in the ShopSite database that is accessible?

Thanks much,
Eddie