def set_oracle_service(sid = nil, username = nil, password = nil)
      self.database  = sid
      self.user_name = username
      self.password  = password
      self.service   = Credential::Service::ORACLE
    end
def set_oracle_service(sid = nil, username = nil, password = nil)
      self.database  = sid
      self.user_name = username
      self.password  = password
      self.service   = Credential::Service::ORACLE
    end
sets the Oracle service.