XML Cheat Sheet – Quick Reference Guide

Estimated study time: 10 minutes.

A quick reference for the XML concepts covered in this course — handy for revision before an interview or project.

Basic Syntax

<?xml version="1.0" encoding="UTF-8"?>
<root>
  <child attribute="value">Text</child>
</root>

Rules to Remember

  • Every opening tag needs a matching closing tag
  • Tags are case-sensitive
  • Documents must have exactly one root element
  • Attribute values must always be quoted

DTD vs XSD

<!-- DTD -->
<!ELEMENT student (name, course)>

<!-- XSD -->
<xs:element name="student">
  <xs:complexType>
    <xs:sequence>
      <xs:element name="name" type="xs:string"/>
      <xs:element name="course" type="xs:string"/>
    </xs:sequence>
  </xs:complexType>
</xs:element>

XPath Quick Syntax

/root/child        select child under root
//child            select child anywhere in the document
//child[@id='1']   select child with a specific attribute
child/text()       select the text content

XSLT Skeleton

<xsl:template match="/">
  <html>
    <body>
      <xsl:value-of select="root/child"/>
    </body>
  </html>
</xsl:template>

Parsing Approaches

  • DOM — loads the whole document into memory as a tree
  • SAX — reads the document event-by-event, low memory use
  • StAX — pull-based, gives the client control over reading
💡 Tip: Bookmark this page — it's designed to be a fast lookup, not a full explanation. Head back to the earlier topics whenever you need the "why" behind any of these.

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