Ok, I think I asked this before A Long Time ago, in a Forum, Far, Far Away (the asp.net forum to be exact), but didn't really get a clear answer then, so I want to try again.

My modules will use another database seperate from the database containing the DotNetNuke tables, and I was wondering other then portability (to Oracle or some other database), is there any valid reason I should use the DAL instead of accessing the database directly in code?

Here is why I ask.  I tried with and without the DAL and there are significant performance differences.  Please do not mis-understand, I am not knocking DNN at all.  However, I will take the path of better performance, unless there is some earth-shattering reason to use the DAL that might impact my DNN site in the future.

As always, Thanks in Advance!!

Greg

Greg - you can most certainly choose not to use the DAL without any problems. In your case, you've mentioned that you want to connect to a different database than what DNN is running on (i.e. DNN running on SQL Server but you're wanting to connect to an Oracle datasource). In this case, yes you can create your version of the data access layer (or even code it directly within your module's code if neccessary).
The advantages of DAL which come to mind are as follows:
a) You can create your module independent of the database access layer and if at some point in the future you do want to create a version of your module that connects to a different data source/database, it's as easy as writing the dataprovider for your module and you're up and running.
b) The DAL exposes methods (ExecuteReader/ExecuteNonQuery etc) which are preferred ways of getting access to the database (now incorporated in EnterpriseLibrary by MS) and as such it becomes easier to write less lines of code to accomplish the same thing.

That being said, what performance improvements are you seeing when not using the DAL?

AFAIK, the difference comes from the expensive use of reflection to be able to use the Provider model for data access. As others have pointed out, if you don't need to make your module portable, there's no reason whatsoever to use the DNN DAL. Of course you do want to keep a layered design and use your own DAL.