>>>>>Succumbed ?
>>>>
>>>>:-}
>>>>Doesn't take me long to get bored with lying by a pool.....
>>>>
>>>>>
>>>>>
>>>>>>What do you mean by "computes the total of a document that can contain up to a few hundred lines."
>>>>>>What document? What computation ?
>>>
>>>And we don't want you to be bored now do we?
>>>
>>>So here's information that will keep you from away from the pool ? I think not :)
>>>
>>>The document could be an order. The computation is the total invoice, the vat, the amount without vat.
>>>The business rules are
>>>- the client has a vat profile (you have belgian clients, EU clients or Exports, clients that are not subjected to vat .... the Belgian vat codex is quite a thick book).
>>>- the client has an default discount
>>>- the client has specific discounts on specific items
>>>- the item is subjected to a specific vat rate
>>>- some items overrule the clients discount.
>>>- ... and here's the kicker, vat needs to be rounded up to nearest (Euro)cent.
>>>
>>>So in my VFP inherited way, I created the ad hoc objects that implement the rules (including data access). It meant that I access multiple tables for each line of the order. Looked like a good idea as it warrants very clear and manageable code.
>>>
>>>The problem is that my VFP days are over, I have to do this the "right" way, which would mean that I need to access the db once and then apply the rules for each line without accessing the db.
>>>
>>>But while the order is being entered, the client wants to see the totals, the vat displayed in real time.
>>>
>>>So I end up with the lines in a dataset.datable that is submitted to dvg. And that is the information taht i need to "join" to actual tables to get myself an ado.net datatable, that I would then scan through to compute the totals. I guess that would go faster because for say 100 lines I only would go once to the db, whereas now I'm gong like 500 times, which on an access db is (that is my assumption) kind of sllllloooowwwww.
>>>
>>>Unless I hear anything more sexy I will implement Borislav's suggestion whereby l compile a huge sql statement (including every key) and submit that to get to my dataset.
>>>
>>>Thanks for caring, and enjoy the pool :)
>>
>>Ta.
>>I don't think it's possible for one to recommend a specific approach without a lot more detail as to how the database is structured.
>>However, as John suggested, you can use Linq to Dataset to do local lookups etc. See if this can give you some ideas:
>>http://msdn.microsoft.com/en-us/library/bb386977.aspx
>
>My Backend is MS Access; I don't think linq is an option.
>
>But tell me, isn't there a way where I can dump my datatable "as is" in a temporary table into the db and then join that? I would then delete the table when I'm done (I promise).

What I was suggesting was 'Linq to Datasets' - you still use basic ADO.NET to retrieve data from the backend (whatever that may be) then, as John has expanded on, use Linq-Datasets to query the resulting tables.