Accessing database or data services from workflow foundation?
===

I'm looking at WCF for a project, and was curious how one would go about exposing data that can be acted on in a WWF workflow.  I can't seem to find anything about accessing data that might be in a database (outside of the SQL Tracking, but I don't think that's what I'm looking for) whether by query or by accessing a data service of sorts.

So, for example, if I wanted to create a WWF web service that determines if I want to insure a house, so it takes in a few parameters (let's say house_value, zip_code) and return true or false based on an algorithm defined in the WWF flow.  Part of this algorithm needs to check crime levels for that zip code to help determine whether it returns true or false.  I have a database table that has crime levels by zip code, so how would I go about querying the crime level from within the WWF flow?  Or alternatively, I know of another service that returns crime levels based on zipcode that I could call, how can I call that from inside my WWF workflow?

(I made up the scenario above to illustrate what I'm talking about, this isn't my real problem)

Thanks in advance!