>I suppose it will depend how the presentation layer is actually reading/writing the data, if it is directly to an ADO then surely this will be going directly back to the data-layer.

Use client-side record sets.

>
>I think this is where I'm getting confused. The way I'm picturing it is the presentation layer receives an ADO from the business-layer, changes are made to some of the fields, then the Update/Cancel methods in the ADO are executed from the business object (upon validation), is that how it would work?

No. The RS is passed from UI to business-layer for validation. If valid, the RS is passed onto the data-tier, which then handles the update. If not valid, return an error message/code to the UI.