Using XSL to remove redundant data

Question

I am trying to produce an XML document from information on our 9i database. Using XDK I am able to produce the following XML document very easily:
<ROWSET>
  <ROW num="1">
    <CUSTOMER_ID>1</CUSTOMER_ID>
    <CUSTOMER_NAME>Cust 1</CUSTOMER_NAME>
    <ORDER_NO>1</ORDER_NO>
    <ORDER_DESC>The first customer's first order</ORDER_DESC>
  </ROW>
  <ROW num="2">
    <CUSTOMER_ID>1</CUSTOMER_ID>
    <CUSTOMER_NAME>Cust 1</CUSTOMER_NAME>
    <ORDER_NO>2</ORDER_NO>
    <ORDER_DESC>The first customer's second order</ORDER_DESC>
  </ROW>
  <ROW num="3">
    <CUSTOMER_ID>2</CUSTOMER_ID>
    <CUSTOMER_NAME>Cust 2</CUSTOMER_NAME>
    <ORDER_NO>3</ORDER_NO>
    <ORDER_DESC>The first customer's third order</ORDER_DESC>
  </ROW>
  <ROW num="4">
    <CUSTOMER_ID>2</CUSTOMER_ID>
    <CUSTOMER_NAME>Cust 2</CUSTOMER_NAME>
    <ORDER_NO>4</ORDER_NO>
    <ORDER_DESC>The second customer's first order</ORDER_DESC>
  </ROW>
  <ROW num="5">
    <CUSTOMER_ID>2</CUSTOMER_ID>
    <CUSTOMER_NAME>Cust 2</CUSTOMER_NAME>
    <ORDER_NO>5</ORDER_NO>
    <ORDER_DESC>The second customer's second order</ORDER_DESC>
  </ROW>
  <ROW num="6">
    <CUSTOMER_ID>3</CUSTOMER_ID>
    <CUSTOMER_NAME>Cust 3</CUSTOMER_NAME>
    <ORDER_NO>6</ORDER_NO>
    <ORDER_DESC>The third customer's only order</ORDER_DESC>
  </ROW>
</ROWSET>I would like to convert it into the following format:
<CUSTOMER>
  <ID>1</ID>
  <NAME>Cust 1</NAME>
  <ORDERS>
    <ORDER>
      <NO>1</NO>
      <DESC>The first customer's first order</DESC>
    </ORDER>
    <ORDER>
      <NO>2</NO>
      <DESC>The first customer's second order</DESC>
    </ORDER>
  </ORDERS>
</CUSTOMER>I presume XSL can do this, but I'm not sure where to start. Could anyone confirm if this is possible, and if so point me in the right direction?
Thanks in advance,
Paul.

Answer 1

Yes, an XSLT can do this. There are a number of free XSL tutorials on the web you can look at to get the basic ideas; when you're ready, I know of no better reference than O'Reilly's XSLT.
XSL, IIRC, is Turing-complete, so there's very little it can't do. But if you're accustomed to procedural scripting you'll have to rewire a bit of your brain, because it is not procedural. Good luck and have fun!