How do I create an xml schema such that in the future when there is a need to enter a completely new object, the schema does not need to be edited? I studied through w3schools and other sites -- but nothing.
I think you're referring to XML namespaces, which allow you to use prefixes to incorporate tags from different schemas.
The example from the linked page:
<?xml version="1.0"?>
<!-- both namespace prefixes are available throughout -->
<bk:book xmlns:bk='urn:loc.gov:books'
xmlns:isbn='urn:ISBN:0-395-36341-6'>
<bk:title>Cheaper by the Dozen</bk:title>
<isbn:number>1568491379</isbn:number>
</bk:book>