70-461 Training Kit Chapter 7, Lesson 1: XML Basics Part II

More XML terminologies.

Element-centric presentation

         Data is stored between start tag and end tag of XML elements.

         Recommendation to store data.

Example:

<Customers>

    <Customer>

 <custid>1</custid>

 <contactname>Allen, Michael</contactname>

    </Customer>

    <Customer>

 <custid>2</custid>

 <contactname>Hassall, Mark</contactname>

    </Customer>

</Customers>

Attribute-centric presentation

         Data is stored inside of element tags.

         Recommendation to store metadata

Example:

<Customers>

    <Customer custid="1" contactname="Allen, Michael" />

    <Customer custid="2" contactname="Hassall, Mark" />

</Customers>

Mixed presentation

XML documents can contain both element-centric and attribute-centric presentation.

Example:

<Customers>

    <Customer>

 <custid>1</custid>

 <contactname>Allen, Michael</contactname>

    </Customer>

    <Customer custid="2" contactname="Hassall, Mark" />

<Customers>

Prolog

Denoting the XML version & encoding

Must be the first line of the XML document

Example: 

<?xml version="1.0" encoding="ISO-8859-15"?>

Namespaces

Declared in the root element

Can have alias

Example:

<Employees xmlns:emp="EmployeesCompanyA">

<emp:Employee>

<emp:employeeid>1</emp:employeeid>

</emp:Employee>

</Employees>

Special characters

<, >, &, ", '

Use & as escape character and end with a semicolon.

Example: $lt; is equivalent to <

Another option: use XML CDATA section as <![CDATA[…]]>

The characters in the … is treated as literal character

Example:

<Product><![CDATA[<<&>" ']]></Product>

Comment
          Syntax: <!-- this is a comment -->

 Example:

<Customers>

    <!-- this is a comment -->

    <Customer custid="1" contactname="Allen, Michael" />

    <Customer custid="2" contactname="Hassall, Mark" />

</Customers>

Processing Instructions

         Syntax:  <?instruction?>

Instruction for application that process the XML document. 

Example:

<?xml-stylesheet type="text/xsl" href="/style1.xsl"?>

XSD (XML Schema Description) Document

Describe the metadata of other XML documents

Can specify: constraints, data type, element names, # of occurrence for elements.

Schema of XSD document is predefined

Typed XML document

When have a predefined schema (from XSD document)

XML Document Validation

A process of checking if the XML document is complied with a schema (in XSD document)

Reference: 

XML 1.0 document Map on MSDN: http://msdn.microsoft.com/en-us/library/ms256153(v=vs.110).aspx

70-461 Training Kit