There is not a full db schema published per se, but take a look at what's available through the Data Extraction Engine (DEE) documentation. Both Campus Manager and RME components allow for data extraction.

See, for example:

http://www.cisco.com/en/US/docs/net_mgmt/ciscoworks_campus_manager/5.1/user/guide/dee.html

http://www.cisco.com/en/US/docs/net_mgmt/ciscoworks_resource_manager_essentials/4.2/user/guide/cwcli.html#wpxref55220

and the deployment guide at:

http://www.cisco.com/en/US/prod/collateral/netmgtsw/ps6504/ps6528/ps2425/ps7196/prod_white_paper0900aecd80663ca6.pdf

If that doesn't suffice, your account manager may be able to link you up with internal Cisco documentation.

Hope this helps. Please rate this post if it does.