[thelist] XML 2.0

Warden, Matt mwarden at odyssey-design.com
Mon Feb 12 15:16:15 CST 2001


> Thanks for the responses! By the way, that description didn't come from a
> design site, I just made it up.
> (By the way, I am writing a easy easy xml introduction for non-techies,
> that's why)

Ok. Have you revised it now?

> Ok, another question.
> Would it be fair to say: the main advantages of XML (from a business point
> of view) are:
>
> - xml is going places

Kind of... except it's something so simple that's it's really always been
here. It's just a subset of SGML, which is older than me.

> - xml is fantastic for exchanging data

YES! You might want to add "securely" to that, because that's the biggie. It
can be sent over HTTP/SSL.

> - xml makes data more useful

Eh, maybe. It makes it easier to manipulate and identify, if I see what you're
getting at. Unmarked-up data:

MattWardenCincinnatiOhio45014UnitedStatesNeonClearCow

Or, even:

Matt Warden Cincinnati Ohio 45014 United States Neon Clear Cow

Huh? Do you know what this data is? Or... will your program be able to
recognize it? Can you gaurentee that the first name will always be there and
the very first part of the string? Willing to risk it? Hmmm... how about this:

<record>
    <name>
        <first>Matt</first>
        </surname>Warden</surname>
    </name>
    <address>
        <city>Cincinnati</city>
        <state>Ohio</state>
        <province></province>
        <postalcode>45014</postalcode>
        <country>United States</country>
    </address>
    <favorite-color>Neon Clear</favorite-color>
    <pet>Cow</pet>
</record>

Can you read it? Can your program/parser? Of course. It just makes it easier
to manipulate or extract pieces of information.

> - xml is futureproof

Yeah, I guess. It would always be an option, but that's not to say that some
"better" technology comes along. It's so simple tho, that it would be hard to
get it to go away.

> And the next question: examples of DTD's. I've been playing with Xmetal
> (xml editor), which comes with a few DTD's. Is there a list somewhere?

You can get on various email discussion lists (if that's what you meant by
list). microsoft.com has a few. w3.org has some too. not hard to find.

> Or
> would it make sense for a lot of applications to make your own?

YES!!! If you're going to use a DTD, most cases you will want to make your
own... unless you're trying to conform to some set of industry-specific
standard (not contradictory, I swear!) tags... then you would use the one that
is available for whatever you're doing.

> Or could
> you just decide on what tags to use and chuck the DTD.

Yup. Not a good idea during development time, tho.

> In that case, the
> list of tags you can use in your own flavour of XML, is a DTD the only way
> to describe that?

NOPE. DTDs are only for the validation of your documents... so you don't use a
<dan-tag /> when that's not a tag you should be using (usually because it's
not being handled by a stylesheet or parser) or if you type an attribute as
vlue='blah' when it should be value='blah'. But there are a lot of other
goodies in DTDs like datatype validation, etc.




--
mattwarden
mattwarden.com





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