Can I embed SQL queries into an xml doc for the purpose of autofilling a web form with database information?
For Example, I want a line for user input:
Customer_ID:[___________________]
And I want it to retrieve stuff like:
Name: Nic Cage
Address: 123 Cage Street
City: Cage
State: CA
Sorry for being so damn vague, but I am quite lost.
XML doesn't have live content like queries (unless you count XQuery to pull populate data from another XML document, which won't apply here). If you're on SharePoint (depending on version, since you didn't specify), you should be using things like Data Sources (set up through SharePoint Designer, Visual Studio or connection libraries) or forms in InfoPath.
If you're on an earlier version of SharePoint (200x) you can write an ASP.net page that has a SQL query that pulls its connection from a config file (though that's outdated)