use a different db but with same table users q2a structure

Question

I read this http://www.question2answer.org/single-sign-on.php , but is possible use for a external db with same structure users table of q2a ? example of strucure that I imagine:

db 1) users external (same tables of origial q2a structure, not other platform) active on login.domainname.com

db 2) q2asite1.domainname.com

db 3) q2asite2.domainname.com

db 4) etc... etc...

Answer 1

See these questions:

http://www.question2answer.org/qa/14055/use-sso-want-add-more-q%26a-sites-that-shares-the-same-user-table

http://www.question2answer.org/qa/5622/how-does-the-multiple-q2a-sites-work-in-1-4

 

Comments

ok, I can use define('QA_MYSQL_USERS_PREFIX', 'qa_users_'); option but this work on same database, so I dont can use different db for every q2a-site.
If i add all tables group of every subdomain how I switch every website on corrects set of tables of question, meta, activity?