Evan,
You can setup a MongoDB database for free and add an API to it (restheart.org). This allows you to access the database with URLFetch in the Wolfram language. This way the wolfram cloud talks to your MongoDB/restheart api you connected to the internet.
I would advise not to use the database available in the wolfram cloud. The java setting have restriction you will run into.
If you have a MS or Oracle sql server running and want to access it via Wolfram Cloud please have a look at Espresso Backend services. Not free but works really well and has a account/security management system.
here is a read with restheart api:
ImportString[
URLFetch["http://192.168.xxx.xxx/course/" <> "collectionname",
"Method" -> "GET"], "JSON"]
this is a write via restheart api:
URLFetch["http://192.168.xxx.xxx/course/student", "Headers" -> {"Content-Type" -> "application/json"}, "Body" -> ExportString[#, "JSON"], "Method" -> "POST"]&
note:keep looking into the Wolfram Language, it can do many things others can't.