Where to place Business rules

I´m evaluating DevForce and i have any questions about the place for some business rules.

 

Imagine an use case to place a purchase order. In the process when a product is selected to the order, i want to verify the existences for the product (how you suggest implement this calidation rule?) , later when the order is placed, in the server i want to make the same validation BUT WITH FRESH stock items, since the stock may be changed in the interim, and if all is correct, then the existences must be updated maybe creating a stock object, or updating a field in the product object.

 

Can you give to me a suggest to implement ths use cas with devforce?

 

With RIA SERVICES I think isolated the business rules in a Domain Service to purchase orders.

 

Excuse my bad english.

 

I have the same question, but it is not related to concurrency.

 

I have other subprocesses related to system-to-system communication that I want to execute.

 

So, I save a transaction and the state of that transaction changes to a state that lets the system know that it now needs to send send a message to another system. I like being able to just change the state of a field on a record and save it, but I do not see how to make DevForce have a server side process that inspects this save and then does other work based on the state and possible reject the state if the other system is down. (I know this last part can be debated, but in the current architecture there is no middleware that can be used to store the message if the other system is down.) 

 

I look forward to learning how to do this in DevForce.

 

Take care...

 

My requeriments is more like Hunter described. I have many scenarios for this, as example:

1.- I have a multilevel net of objects where the cost of an object is the sum of the previous level of objects, in such case i want to make persistent the cost of the object as the sum of your object components to avoid load the full net when i need the cost of a object in top levels. For this, in legacy implementation when a object in low level is saved i recalculate the cost of the parent level as cost += objectchild.cost - objectchild.originalcost.

2.- When i save a purchase order item, i need to CREATE an object to save the  stock for the associated product, i need intercept the save of purchase order item an as part of the same transaction create the stock item.

 

I dont like the save interceptor because i think that the onsaving event should be an "as class" event to encapsulate the logic by each class and not for all class entities. (I have used XPOBJECT ORM by DevExpress and using the Onsaving event in my object to ths business rules)

 

Do you have another alternative to my requeriments?

thanks.