Apprentice XML

Table of content

 

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Prerequisites

 

• A good knowledge of html basics programming. Basic html programing tutorials

 

• Notepad ++ https://notepad-plus-plus.org/

 

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A. What is XML?

 

 

• XML stands for eXtensible Markup Language.

 

• XML is a tag-based syntax like HTML <h1> </h1>, however you can create your own tags.

 

• XML is used to structure and describe information.

 

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B. XML Trees

A simple XML tree has a root and an element.

Example of a simple XML document.

1. In Notepad ++, type:

<store>
<product>
PS4
</product>
</store>
 
2. Save the document as Product.xml.

3. Run the document in the web browser. 

Result: 

Lets at a slightly more complex XML tree.

1. Type:

<Food>

<Fruits>

<Fruit1>
Coconut
</Fruit1>

<Fruit2>
PineApple
</Fruit2>

</Fruits>

</Food>
 
2. Save as Food.xml

2. Run in the web browser.

Result: 

Now lets look at a XML tree having attributes:
 

• When coding in HTML we can add attributes to tags to style them. However in XML attributes are used to differentiate information as shown in the example below. 

 

• Also XML attributes are often use as metadata (information describing other information); for example order IDs.

1. Type:

<store>

<Game category="PS4">
<Title>
Driveclub
</Title>
</Game>

<Game category="Xbox One">
<Title>
Froza Horizon 2
</Title>
</Game>

</store>
 
2. Save as Store.xml.

2. Run in the web browser.

Result: 
 

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C. Rules 

XML elements:
 

• requires an openning and a closing tag <...> </...>

 

• are case sentitive. <A>...</A> is different from <a>...</a>

 

• requires proper nesting as show below.

Correct nesting
<a>
<b>...</b> 
<a>

Incorrect nesting
<a>
<b>...</a>
</b>

XML attributes values requires quoting "PS4". <game category="PS4">...</game>
 

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D. XML Comments

Creating XML comments is fairly simple as shown below.

<!-- Hello World -->
   

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E. Namespaces

 

• Conflicts occur when your using 2 XML document with similar tags. To avoid conflicts we use prefixes. In order to use a prefix in XML, we need to define a namespace for the prefix.

 

• The xmlns attribute is utilize to define a prefix as shown below.

 

• A uniform resource indicator URI is used when defining a namespace. You can learn more about URI using the following link: http://searchsoa.techtarget.com/definition/URI   

<root>

<f:table xmlns:f="FruitsURI">
  <f:tr>
    <f:td>Coconuts</f:td>
  </f:tr>
</f:table>
 
<v:table xmlns:v="Vegitablesurl">
  <v:name>Carrots</v:name>
</v:table>
 
</root>
 

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F. Next Step

Feel free to practice all the concepts you learned in this tutorial using Notepad ++.
 

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