Thread: XML overview

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    XML overview


    OK I am familiar with the basics of XML. But why is a user definable markup language so valuable. Can someone give me an overview of the key features that make XML so great?

    Thanks!
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    I am no expert - in fact I am reading more about XML now to discover how to use it myself. However, the way I have understood XML is that it is somewhat generic data type that can be shared accross many different platforms and instruments. For instance, say you create a database of widgets at your company. Say, I create a website that sells your widgets. Your data and my data are the same XML data. Your database knows how to read, process, and manipulate the data and I program my store to read, process, and manipulate the same data. The data never changes format, therefore it is universal. Now, say someone else creates a way to display your XML data on a web-enabled phone, or a PDA.... see the usefulness? XML can be used on any platform (Unix, Linux, Windows, Mac) and can be read, processed, and manipulated by any XML enabled software.

    Now my job as a web developer is to write scripts and applications that can read, process, and write to XML data.

    I am sure that this just scratches the surface of XML. I am dedicated to finding out all I can since I can't seem to find a job description out there these days that does not list XML in its requirements.

    Hope this helps,
    Zach

    Anyone one else want to add or refute?
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    Exactly as he said it. So you have XML code:

    <tshirts>
    <striped>
    blah
    </striped>
    </tshirts>

    Now just add say CSS or XSL and manipulate whatevers in there, and it's all fine and good here. But lets say there's a completely different languaged wanting to be used on a cell phone? A smaller language? They could take the same XML code, but use the different editing technology. XML is just what HTML started out as, but HTML evolved so that it could give webmasters more control, therefore making the language huge, and a browser that size will not fit on a cell phone. This is one of the main purposes of XML. HTML will phase out in a while, XHTML will last a for some years then faze out, but XML is here to stay for a while. XML can be written to by all languages, and is very small. See how great it'll be? It's not very hard to learn, but until DOM kicks out CSS (hopefully that won't be for a decade or more ) I'm not gonna bother with XSL(XSLT, whatever). It's more complicated than it should be to get the same job done you could have with CSS. And some of it's 'usefullness' could be done with a bit o PHP also.
    You know your a web programmer when you see a '$' and think of PHP rather than money.
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    Question


    Hmm I think I understand that it is useful to have the data compatible in multiple platforms and such, but I don't get how the arbitrary tags make this so; how does having text wrapped in a series of arbitrary tags make the document more widely usable?
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    The beauty of it is: XML only puts out data, it does not alter or expand on it in any way. So you have another language that can manipulate XML but XML will not manipulate when it's just alone. Other languages have ways that will let you manipulate them, such as HTML, which make them bigger in the browsers. Browser size did not used to be a big issue, now it is. Hence, XML was created. Did I answer your question? This is why it will be more widely used, because it can connect to so many different languages and is so small.
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    Could you give an example of HTML using an XML document? Like how does it reference the XML mark-up?
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    http://www.hawaiiycc.com/text_display.php

    That's an example of an XHTML document.. An XML document with a DTD that defines for it HTML elements.
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    XHTML and XML are quite different. XHTML was just a way to make HTML smaller and to save it's butt. But frankly, XHTML will only last some years more as well. XML is meant to be used with languages with such as CSS, XSL, or any other technology like those two. I use CSS. But if you want to you HTML, then XHTML is the way to go cause HTML will be out in a very few short years. It's just to big...

    but then again the "when a technology is gonna be out" is just my opinion...

    If you want to be XHTML complient the W3C has an online XHTML checking system to make sure your XHTML is good. But not to get into a long XHTML tutorial on this board, just check out the link and some other links as well. I think this was a good site for it where I learned:

    http://www.xhtmlguru.com
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    I can't argue with you, but MaxC wanted to know how a HTML document can reference and XML document. The truth is, HTML can't do something like that per se.

    Someone here said that an XML document only 'puts out' data. That's true in a sense, but I'd rather say that XML structures and stores data so that other tools can be used to 'put out' data. HTML, unfortunately, isn't one of those tools.

    However, that being said, I posted the XHTML example to show that while XML doesn't neccessarily do anything like HTML, XHTML, which I'd say is technically an XML document, can take the same principles and display them like HTML.
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    ya I got that, but I didn't think he would
    You know your a web programmer when you see a '$' and think of PHP rather than money.

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