Bingo, exactly what I needed to know.

Thanks for your help, in other threads too.

Kev

>The middle tier should have an AddUser method that does the following:
>
>1. Call validation methods if any are needed.
>2. Pass the data onto the AddUser method of the data tier.
>
>The business tier should have no knowledge of how the data is actually saved. (Is it an INSERT, an APPEND BLANK, a SQL INSERT?) The business tier neither knows nor cares. The data ojbect handles the actual implementation of the insert (or however you implement it).
>
>
>>Marcus
>>
>>I'm currently working on a very simple app in order to get me into this.
>>
>>I'm starting with a simple business object for USERS. What I've done so far is have a USER Data-object, and a USER business-object. The USER business-object creates the USER data-object and uses that object to obtain data from the USER table (talking in ADO).
>>
>>One of the things that's stumping me is, where to insert/delete records from? The middle-tier or the data-tier? If I insert a new record do I need to pass the data-object all the field values etc?
>>
>>Am I on the right track?
>>
>>Thanks
>>Kev