Monday, March 12, 2012

7 Important XML Terms And Concepts

XML stands for Extensible Markup Language. 

1. Meta Language:
XML is a meta language. Meta languages are used to store information that may be accessed by multiple different platforms. XML is often used to communicate information from one application to another.

2. Extensible Markup Language (XML):
XML is similar to HTML mainly because the two are both mark up languages! (XML HTML). XML is extensible because it has no presentation semantics, unlike HTML which does have presentatin semantics. Presentation semantics describe how data has to be presented/interpreted.
HTML is a markup language which is delegated by tags, elements, attributes and structure.

3. Tags:
Tags are each angle bracketted piece of text in the XML file. So, if you saw <Dog> then you would know that that is the Dog tag (specifically the opening tag for Dog). Most tags have a opening and a closing tag. For tag <Dog> (opening) there would be a corresponding </Dog> tag.

4. Text Content: 
Describes the text found between two opening and closing tags. This may include other tags nested inside the original tag of concern but are usually angle-bracket-and-other-syntax-free.

5. Element:
In XML an element is the unit that describes a set of matching opening and closing angle tags.
<Day></Day> would be an example of an element. Day would be the name of the tag, but the pair and all its contents embedded inside it, together, would be a element.

6. Declaration Statement: 
At the beginning of XML documents it is important to have a declaration statement, because it describes the version of XML the computer will be interpreting. A declaration statement can look like this: "<?xml version="1.0" encoding="utf-8"?

7. Parent Tags:
Parent tags encloses (nests) as many or as little child tags as the creator of the XML file would like. For example, in my sample code (below) ParentTag is the parent of ChildTag1 and ChildTag2.

Why use XML? 
-core of web developements
-used in popular sites across the web

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