XML Tree Structure

Estimated study time: 11 minutes.

Every XML document is structured as a tree — a single root element branching out into child elements, which can themselves have further children. Understanding this tree structure is essential to reading, writing, and navigating XML correctly.

Visualizing the Tree

<course>
  <title>Data Analytics</title>
  <modules>
    <module>Excel Basics</module>
    <module>SQL for Analysis</module>
  </modules>
</course>

Here, course is the root. It has two children: title and modules. The modules element itself has two children: module and module.

Why the Tree Model Matters

• It mirrors how most parsers (like the DOM) represent the document in memory.
• It makes navigation predictable — you always move up to a parent, down to children, or sideways to siblings.
• It's the foundation for query languages like XPath, which describe paths through the tree.

Tree Terminology

• Root — the single top-level element containing everything else.
• Branch — any element that contains other elements.
• Leaf — an element with no children, usually holding text content.