Hi Serge,

One of the reasons I use XML for relational databases, is that you don't
have to pay for any licenses, and you can share and manipulate the data
across disparate platforms such as UNIX, Linux, Windows.

With Sun Microsystems servers and the latest UNIX XML parsers, you can
get extreme performance with block-level full-text indexing. Add PERL to
the mix with inverted tree capabilities, and you are blasting your way
to the future. By using XML, you would also be geared up for
server->server communications with other businesses.

XML shines when sending data between different systems, working with data
from customers, vendors, etc. We have created XML files that are cached for
static data....I have seen some work done where pages were rendered from XML
via XSLT and to me it's a nightmare.

Does anyone use XML/XSLT to render web pages?

To exchange documents in an environment where neither side wants to
depend on the technology the other party uses you need a common language
in which to write these documents. XML is the defacto standard-language.

XML is a flexible way to create common information formats and share
both the format and the data. Because data is represented as plain text
in XML documents virtually any computer system can parse XML documents
and use the data. XML is therefore the preferred data format most of the
time.

XSL or XSLT is used to transform an XML document to another document
structure. The transformation target is usually plain text, HTML code or
another XML schema. Although XSLT can be difficult to understand at
first, it is an immensely powerful tool. If you need to convert an XML
document to another format, for example when integrating disparate
systems, or you want to present XML data in an HTML page, XSLT is often
perfect technology to use.

Anders Norås
http://dotnetjunkies.com/weblog/anoras/

Hi Serge,

First off, you may want to read up on Service Oriented Architecture.
Here's a link to one of Pat Helland's recent articles
http://msdn.microsoft.com/library/default.asp?url=/library/en-us/dnbda/html/data
outsideinside.asp

XML is useful if you need to communicate complicated data in a standardized
way.

It is best used when communicating from system to system, as some of the
other responders have implied.
Since I can create a schema that defines the RULES that a valid XML document
must follow, I can pass a schema to my trading partner, and they can write
software that will meet the schema, and I can commit to them that I can
accept the data they write.  This is a Dramatic improvement over current
practice when integrating systems.

That said, I've also used XML as a mechanism to store "semi-structured"
data.  This is data that, from the standpoint of the storage system, is
essentially a BLOB, but has a structure.  For example, if I have a wide
range of XML documents stored in SQL Server 2005 (Yukon), I can store the
documents into an XML field and query on the data in a very flexible manner.
I could have 10 rows in an inventory table, where the first five rows store
data about computers, and the next five rows store data about monitors.  The
XML structure can be defined so that there are common elements dealing with
inventory tags and locations, and embedded elements dealing with resolution
(for monitors) or CPUs (for computers).  I can issue a single XQuery against
this table and retrieve all the inventory tags, and another XQuery against
the table and retrieve all the CPU information for the rows that deal with
computers.

This ability to store semi-structured data is very powerful in many ways.

I also use XSLT to transform XML documents into other formats, although I'm
not well versed in the XSLT language (I use tools mostly).  For example, I
have a workflow system that manages any number of different workflow
documents.  Each document type comes with an XSLT that allows my GUI to
display information about the workflow item without my GUI needing to know
anything about the structure and format of the workflow document itself
(another example of semi-structured data).

XML is not a silver bullet.  It doesn't solve every problem.  However, it is
a very useful technology to add to your tool belt.