automatic generate sml schema

Hello all,

I am new to XML. I would like to ask you a question. Is it possible to 
generate a schema file from an xml instance file? That is, I have an XML 
isntance without its schema and I would like to generate its schema. I 
can do this manually by using xmlspy or some other tool. But it would be 
great if there were a tool to come up with a basic schema that I could 
enhance manualy later. Is it possible?

Thanks,
C.F.