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XML Tutorials and Info

Hi Everyone,
Does anyone have any good links where I could get a quick grasp of XML? I have a client who wants a site built in XML and I don't really "get" the difference between HTML and XML. I bought the XML O'Reilly book ... but I'm lost. thanks,


There's a bunch of xml stuff out there. One that starts right off with 'Intro to XML, what is XML and how does it differ from HTML?' is http://www.w3schools.com/xml/default.asp

Haven't been through in depth so can't personally comment but it looks good on the surface.


Thanks! I've gone through the first chapters, up until the Advanced section. I get it! It actually makes sense to me, as far as how to write XML. What I don't get is where XML would be used.

I'll never forget when I went to computer school for a 9 week course back in the 80's. I understood how to do everything they told me there, but I couldn't figure out how what I was doing applied to what I would do being an employee of a company and using a computer for them. Sort of kin to taking a picture with a digital camera and then saying "Okay, I took a picture! Now what do I do with it?"

So..I understand how to write something in XML, but what do I do with it?


That is exactly the same question I have about XML. It seems like every time I start to study it, I get through many chapters on what is "Well-formed" but no clue as to why I would really want to know that.


LOL. I like that question..."Why WOULD I want to know that?" LOL

Here's what I think (excuse the naivety/stupidness):

I think XML is for office-type applications. It's a computer language a document can be written in, so that businesses can email these docs to whomever they need to. The sender doesn't have to worry about what format the recipient can read...cuz everyone, no matter what OS or software they use, will be able to read it.

As far as us web designers go, I don't think we need to know that for designs or graphics, but we need to know it in case we have files posted for others to read, so they can download them and it'd be the correct format. Plus, I think you can insert the text portion of your website in XML...but I'm not sure why or how it'd be used there.

Or maybe not. ;-)


boy, do I have the same questions - my tentative conclusion is that it is more than I need to know. Just struggled with an xml class, again, through SmartPlanet and got a little further but I still just "don't understand" what it is or how I would use it.

during the class, did find this article, http://alistapart.com/stories/usingxml/ and it helped me understand it, somewhat, a little bit more (at least how it could be used).

got far enough into the class, this time, to discover how complicated it is .... I think, maybe, the kind of work I do I really don't need to know it - or, maybe, rather, there are more important things for me to learn.

really glad to see this thread here though and more confessions of ignorance! :-)


> As far as us web designers go, I don't think we need to know that for
> designs or graphics, but we need to know it in case we have files posted
> for others to read, so they can download them and it'd be the correct
> format. Plus, I think you can insert the text portion of your website in
> XML...but I'm not sure why or how it'd be used there.
>
> Or maybe not. ;-)

Not exactly ;-)

The purpose of XML is to make databases of information more portable. With XML, information from different databases, say a publisher and a bookstore, can be shared. Say the publisher uses an IBM mainframe to house their database while the bookstore uses SQL Server. Chances are the publisher and the bookstore have used slightly different field names, and the technologies can't directly communicate with each other. If there was an industry-standard schema for describing books (which there probably is by now), then an XML document could be an intermediary between the two incompatible databases, reading from one and writing to the other. This would eliminate the need to export data from one database and import it into another.

The XML document could also be used to present information from the databases to a browser, using stylesheets to specify how the information should appear - for example, different branches of the bookstore in different parts of the country could use different stylesheets to match their different Web sites (<book-title> looks like this and <author> looks like that, etc.). So the master database is in the IBM mainframe, the corporate office of the bookstore taps into it to retrieve information about books it has bought from that publisher, and the bookstore branches present that information in a way that goes with their Web sites. Because there is a publishing industry standard schema, the bookstores can use the same stylesheets on database information from all publishers they purchase books from.

HTH,


What would I need to write xml? Do I need to buy new software or anything?


You can use any text editor, or make sure to save as text.

There's a beta version of an XML editor available from the company that taught the XML workshop I took at Web2000DC: http://www.architag.com/xray/


I see there being 2 driving goals behind XML development.

1. Sharing of information. It provides a seamless way to make content transferrable to people regardless of platform and desired use.

2. Separation of content and style. This is something you are hearing more and more about with the Standards movement. Stylesheets seems to be the first step, to pulling the "appearance" elements out for simpler site management and easier changes to the design. The next big step seems to be pulling the content out with XML. The resulting page is really a framework that integrates the stylesheet and the content stored in XML data. The advantage is to be able to drasticaly reformat the content based on who your audience is.

Imagine creating a site where you can service Palm Pilot users, mobile phone users, computer users etc...all by serving different stylesheets. Your basic content pages never need to be altered to accomodate them.

Also imagine being able to give a self updating client access to their content to update to their hearts desire, yet they never have the ability to get into the stylesheet or the basic framework of the site to mess things up.

These things can both be done now, but in ways that are no where near as elegant as xml is leading us towards.

I think it is definitely worth learning this stuff.


Thanks,

That is helping to put things in perspective. I think what I need to do now - given a little time - is to try a little project to really see how this works. I do use databases and style sheets now. I know once you start working that way, you never look back, because it's so much more efficient for handling so many of the tasks we do than static pages are. The part to the puzzle I need now is to figure out how and why the XML is better at doing this than the databases are. I guess I'll have to roll up my sleeves and get into it - and then it will probably clear up.

It does appear that the browser itself (if it's XML capable) can do more to manipulate the XML data than the data served by the normal database application. In the latter, all of the manipulation is done on the server, and the client receives a static page. In XML, do the style sheets control the "fields" that are displayed for the different devices, as well as the text formatting, etc.? It seems to me that you might choose to display fewer "fields" for the cell phones and PDA's than you would for a normal Web browser.


:: The part to the puzzle I need now is to figure out how and why the XML
:: is better at doing this than the databases are. I guess I'll have to

Might not necessarily be "better" for a specific database app that you have in mind. Just different. The advantage comes in when you might want to use the stored data for more than just database work. Say you are a large company and you want to put a master contact list out there for all of your different regional offices to use.

- A receptionist might want to pull that data into a publishing program to format a nice contact list for the boss

- A sales person might want to bring that data into their palm pilot's address book

- A regional office might want to pull that data into their local Microsoft exchange server to make a master address book that all of the Outlook users in the office can access

etc...

with xml data all of that stuff would be possible with the same file. It might not be so portable if the data were only available in SQL server for example.

:: devices, as well as the text formatting, etc.? It seems to me that you
:: might choose to display fewer "fields" for the cell phones and PDA's
:: than you would for a normal Web browser.

That's where the css comes in. css has a "display" property that can be set to "none" That would essentially make the field disappear. You could use that property in your PDA stylesheet for the fields that those browsers don't need to see.


 

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