information about the underlying data-model behind civicrm (version 4.6)
There is some data information on the wiki:


https://wiki.civicrm.org/confluence/display/CRMDOC/Database+Reference    - 
https://wiki.civicrm.org/confluence/display/CRMDOC/CiviCRM+data+architecture    
https://wiki.civicrm.org/confluence/display/CRMDOC/CiviCRM+4.4+ER+Diagram


I hope this helps you!