HOW to implement a Configuraction table

Hi, the question is simple.

Sometime you have a configuration table where you store for example transaction numbers or invoice numbers.

In the MVC schema, how this is implemented?

In old fashion way i have a function : getNewTransacctionNumber()

and within that I create al the SQL statements necesary to retrive the column number, add 1 and store new value.

I suppose that what I need is to create a Method in Model class, to retrieve the new value.

ConfigClass::Model->getNewTransactionNumber()

In that method , using AR I could retrieve, add and update the value.

Am I in the right way ?

Best Regards

Check this extension: http://www.yiiframework.com/extension/config