short notes is a journal on software, systems, engineering practices among other things.
Copyright © 2002-2006 short notes. All rights reserved.    contact address: email to the editor   ISSN 1543-6489

short notes
 

XML Schema and Query - star crossed lovers?


XML-DEV blog eclectic reports that many people are discussing whether they need W3C XML Schema to use XML Query and the discussion is getting quite heated with some memorable words like "[Schema is] an environmental disaster".

This kind of discussion at this point in time does not bode well for both Schema and Query, whose specs have been around for quite a few years.


 
permalink   
 

What ails native XML databases?


In the beginning, XML database vendors would tell a story:

As more and more data are stored in XML format, it is best to store and process XML in environment and platform specifically designed for XML using technology built for this express purpose ie XML database.

Problem was that almost nobody bought this story. There were few reasons to put data into XML databases because of

Kimbro Straken (of Apache Xindice nee dbXML fame) writes there will be room for embedded XML databases but native XML databases are doomed given that Oracle 9i and other RDBMS are for all intents and purposes native XML databases.
 
permalink   
 

XML schema languages, PSVI, Infoset


Out of many candidates for XML schema language W3C XML Schema is the only one to introduce PSVI or post-schema validation infoset. PSVI is returned by schema processor analogous to how Infoset is returned by parsers. Infoset is "an abstract data set ... that provides ... definitions to refer to the information in a well-formed XML document"; PSVI works for validated and well-formed XML document. PSVI provides not only information on validation of an XML document but also type information on elements and attributes as well as their default values. And yet even W3C working group does not have use cases!

PSVI inevitably raises many questions:

Especially PSVI's type system already generates strong objections and dissents like "One typesys to rule them, and in the darkness bind them."

PSVI will affect the future of XML profoundly, or will it?
 
permalink   
 

Against W3C XML standards


Simon St Laurent summarizes the most contentious issue facing XML digerati: "Rising Rebellion Against W3C XML Schema". Many developers are looking for alternative schema languages because they are afraid of massive complexity of Schema standard. Currently there is no clear winner.

Schema is already well-established and making far-reaching impacts on other standards eg SOAP, XPath 2.0, XSLT 2.0 and XML Query 1.0. Because XML Query is trying to be statically typed query language, it needs Schema; because Query is to embed XPath, XPath 1.0 is to accomodate Schema and become 2.0; because XSLT uses XPath, it too becomes 2.0. As XPath and XSLT get "upgraded" they will be incompatible with the original 1.0. Even though some part of the upgrade may benifit users, much of the changes are happening for the sake of XML Query 1.0.

Unfortunately XML Query 1.0 when it's delivered some time in the future will not have CRUD capabilities. (It cannot update nor delete.) Once native XML database vendors disappear, who will use this language?

Maybe this year (2002) we will get an answer to the question of schema language after two years of debate and also see MathML, SVG, SMIL and others finally become usable and useful after many years of promises. There are still six months left.
 
permalink   
 

IETF's guideline on XML


"Guidelines for the Use of XML within IETF Protocols" is currently in draft stage but it is still useful for XML application developers.

The guideline can be summarized as "keep it simple, stupid" or KISS. Avoid processing instructions, entity declarations and references; be careful with namespaces; beware of whitespaces; think twice before using attributes or even worse their default values, and so on.

When will W3C provide a guideline on what processing XML means?


 
permalink   
 

eclectic - the XML-DEV weblog


Because XML digerati are rather loquacious, mere mortals are indebted to Leigh Dodds' "eclectic", the XML-DEV weblog for summary. Many links to XML issues that appear in short notes on 2002-07-01 come from "eclectic" and many articles by him and others from xml.com.


 
permalink   
 

Berkeley DB goes XML


Sleepycat will ship Berkeley DB XML, a native XML database later this year (2002). This is an interesting news considering how poorly native XML vendors are performing these days. Unlike the native XML vendors (eg Software AG), Sleepycat does not face competition from Oracle, IBM and Microsoft (who all support "native" XML in their latest offerings). Given Sleepycat's reputation of delivering tightly engineered products, Berkeley DB XML is something to look out for.


 
permalink   
 

 
Published since 2002-04-23
Updated: 2010-10-16
status
Youre not logged in ... Login
menu
November 2024
SunMonTueWedThuFriSat
12
3456789
10111213141516
17181920212223
24252627282930
October
recent
recent

RSS Feed

RSS integration

Made with Antville
powered by
Helma Object Publisher