Schema documentation for Jamf Database?

No.

The way i've considered it the Jamf Database is Jamf's.. The jss is mine to muck about.

@powellbc just +1 to what @rderewianko said.

jamf have stated before at JNUC etc that the DB is there's, for us we should look to leverage the API.

Well there are reasons to use the DB instead of the API. For reading it's way faster ;-)
For writing I'll always choose the API, as everything else would fuck it up.

But you've got to search yourself through the DB.
I got the following answer from the Support once:

[...] so I'm afraid its down to your own reverse engineering.

https://dev.mysql.com/downloads/workbench/

@donmontalvo That is what I have been using all these years.