[Zope-DB] Start using Z SQL method

[Mahdi Hajimoradi]

I have recently started to use Zope with MySQL and have encountered some
 problem at first.when  i try to add Z SQL method i recive the folloing
message:

There are no SQL database connections. You need to add a Zope SQL database
 connection before you can create a Zope SQL Method.

Dose anybody can help me to start this method?
Some overview,reference would be nice here....

TNX in Advance
--M. HajimMoradi