I'm new to the .Net world. I'm creating a website. It has DAL & Presentation Layer. As I mentioned earlier I'm a novice & I'm not sure how to create a BLL. So I was wondering if my current approach is fine? Will it cause any problems? Its a simple application which queries the SQL Server Database, Selects & Updates the Tables. Please help me understand this better
You really should have more attention to the tags. Please before posting another question here on StackOverflow, read the http://StackOverflow.com/FAQ, http://WhatHaveYouTried.Com and https://meta.stackexchange.com/questions/128548 thanks!
Look up CSLA for a good example of what a good BLL is and does...
I suggest you don't bind your Presentation layer (ie user controls) to your DAL directly instead make an "Object Model" - ideally a nice, encapsulated, polymorphic, abstract API - sometimes referred to as a Domain Specific Language (ie DSL) that ties your DAL to any (client-side, mobile, etc) GUI through binding. Trust me, this will make writing tests much simpler.
That's a summary of the premise behind a BLL with reference to your example.