contentformatter and deliverychannel?

Hi,

I'd like to make a delivery channel that will log to a database
table. It seems that I'd need to have a custom formatter so format
the notification (xml maybe) so that the delivery channel can properly
read it.

Is is considered bad practice to have a deliverychannel which depends
on a specific formatter?

My end goal is to have an application which is a "subscriber" and this
application will manage other subscribers. The application will
receive a subscriber id and a flag to indicate if the subscription
should be enabled or disabled (and in either case, the subscription
would be created).

Thanks
Andy