Hi Janet, On 12/20/06, Janet MacKay <[EMAIL PROTECTED]> wrote: > > Since you mentioned DAO's..
Just to clarify ... when I mentioned DAOs, I was using the term generically; that is, to apply to both gateways and data access objects in the smaller sense. In other words, a gateway is a type of data access object; but the same term/acronym - DAO - gets applied to the object that deals with a single row of a table. > Most of the gateway examples I've looked at _basically_ perform read > operations only. Where do multiple deletes or smaller update operations fit > into the picture? For example a method deletes all records matching a list > of ids or updates only one or two fields (like shippingDate) of 1-n records. First, let me say again that if there's one thing I'm learning about object-oriented architecture, it is that you are constantly making choices on whether to follow strictest "best practices." There's a continual trade-off between keeping everything clean and separate and overcomplicating your application. While I'm at it, I'll suggest that you join the CFC-Dev list (also at House of Fusion), since it's focused on CFCs. And perhaps if you go a little further, you might want to explore the mailing lists for one or more of the MVC-based code frameworks like Model-Glue or Mach-II. Even if you're not interested in using a framework, these lists often contain just the sort of architectural discussions you're wrestling with. Now -- back to your question: certainly there's nothing wrong with putting these methods in a gateway. In particular, the multiple delete makes sense there, because you're going to basically say "DELETE FROM table WHERE id IN (#myList#)" or "DELETE FROM table WHERE someField = #someValue#." It would be silly to do the deletes individually. As far as the updates go -- it depends. (That's a phrase you'll hear every two seconds in object-based architectural discussions.) If you're just gathering up some record IDs and applying an update to a single field, you may want to put the method in the gateway -- because the SQL would be just about as simple as the above "DELETE" statement. On the other hand -- let's say your user is working with a page where s/he might be changing values for several records, but might be updating different fields for different records. In that case, since you don't know what's been changed for any individual record, you can't do a bulk update. So naturally, you need to grab all the values for a given record, whether they've changed or not, and update that individual record -- through a DAO. One guideline that's been helpful to me is this: if you operate on multiple records with a simple SQL statement, just put it in the gateway. After all, one big point of all this object-oriented stuff is to keep things simple and encapsulated, easy to find and easy to maintain. Don't let theory keep you from doing what makes common sense to you. -- Thanks, Tom Tom McNeer MediumCool http://www.mediumcool.com 1735 Johnson Road NE Atlanta, GA 30306 404.589.0560 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~| Create robust enterprise, web RIAs. Upgrade & integrate Adobe Coldfusion MX7 with Flex 2 http://ad.doubleclick.net/clk;56760587;14748456;a?http://www.adobe.com/products/coldfusion/flex2/?sdid=LVNU Archive: http://www.houseoffusion.com/groups/CF-Talk/message.cfm/messageid:264617 Subscription: http://www.houseoffusion.com/groups/CF-Talk/subscribe.cfm Unsubscribe: http://www.houseoffusion.com/cf_lists/unsubscribe.cfm?user=89.70.4
