[XSL-LIST Mailing List Archive Home] [By Thread] [By Date] [Recent Entries] [Reply To This Message]

RE: How to transform flat structure into hierarchical one?

Subject: RE: How to transform flat structure into hierarchical one?
From: "Paulo Gaspar" <paulo.gaspar@xxxxxxxxxxxx>
Date: Wed, 7 Jun 2000 18:59:16 +0200
advantages of flat structure
> -----Original Message-----
> From: owner-xsl-list@xxxxxxxxxxxxxxxx
> [mailto:owner-xsl-list@xxxxxxxxxxxxxxxx]On Behalf Of Kay Michael
> > Here he does not mean group as in "GROUP BY" but simply as putting
> > related records next to each other as in "ORDER BY". Don't 
> > think in SQL all the time - English is trickier than that.
> > 
> Yes, I was speaking generically. But you can go further than SQL 
> ordering to
> make the transformation easy, for example you can start with a SELECT
> DISTINCT and put a list of distinct key values at the start of 
> the XML file:
> it's then easy to work through the distinct values and for each one use
> key() to find all the actual records with that value.

As the case was presented that would mean executing 2 queries without
data duplication savings. I also do not see the possible XSLT becoming 
much more efficient so... my guess is that it would be slower.

But that principle would apply with bulky master data. 

A classic example is the Invoice/InvoiceRows - onde does not want to 
duplicate a massive invoice header per each of its rows (wich usualy hold 
less data than the invoice header). The duplication would produce a huge
extra amount of XML to be parsed.

> Another way to tackle this problem is not to generate an XML file at all.
> Instead the program that queries the database can offer the data 
> to the XSLT
> processor as a stream of SAX events. It's then easy for it to 
> slip in extra
> startElement and endElement events when the key value changes.

That is a damn interesting method.

I am not going to use id in my "nice" ADO2.5/MSXML3 framework where so
much is already there, but I am planing the move to a Java environment
(probably Oracle's) and then...

(Yeah... Java is slower but I am not blind to the advantages.)

Have fun,

Paulo Gaspar

 XSL-List info and archive:  http://www.mulberrytech.com/xsl/xsl-list

Current Thread


Purchasing Stylus Studio from our online shop is Easy, Secure and Value Priced!

Buy Stylus Studio Now

Download The World's Best XML IDE!

Accelerate XML development with our award-winning XML IDE - Download a free trial today!

Don't miss another message! Subscribe to this list today.
First Name
Last Name
Subscribe in XML format
RSS 2.0
Atom 0.3
Site Map | Privacy Policy | Terms of Use | Trademarks
Free Stylus Studio XML Training:
W3C Member
Stylus Studio® and DataDirect XQuery ™are products from DataDirect Technologies, is a registered trademark of Progress Software Corporation, in the U.S. and other countries. © 2004-2013 All Rights Reserved.