Our client has a MS SQL database that has 1 million customer invoice records in it. Using the database, our client wants its customers to be able to log into a frontend web site and then be able to view, modify and download their company’s invoices. Given the size of the database and the large number of customers who may log into the web site at any time, we are concerned about data base engine performance and web page invoice rendering performance. The 1 million invoice database is for just 90 days sales, so we will remove invoices over 90 days old from the database. Most of the invoices have multiple line items. We can easily convert our invoices into various data formats so for example it is easy for us to convert to and from SQL to XML with related schema and XSLT. Any data conversion would be done on another server so as not to burden the web interface server. We have tentatively decided to run the web site on a .NET Framework IIS web server using MS SQL on MS Azure. How would you suggest we structure our database for best performance? For example, should we put all the invoices of all customers located within the same 5 digit or 6 digit zip codes into the same table? Or could we set up a separate home directory for each customer on IIS and place each customer’s invoices in each customer’s home directory in XML format? And secondly what would you suggest would be the best method to render customer invoices on a web page and allow customers to modify for best performance? The ADO.net XML Data Set looks intriguing to us as a method, but we have never used it.