You need to data the data from the SqlDataReader and put it into a collection that implements either the IList or IListSource interface such as Dataset or Datatable.

Creating the relationships ensures database integrity. If there is a relationship between table A and table B, where table A's PK is a FK in table B, then SQL server will not allow you to delete records in table A that has child records in table B. I would not be surprised if there were not also performance benefits when joining table A and B aswell but I am not sure if this is the case.

I would recommend using which renders as a div but has more strongly typed methods. Also, while it contains no data I would set it to not be visible. i.e. under your current HTML Then when you get the data back use: pnlData.innerHTML = YourHTMLString; pnlData.Visible = true; in your code behind.