XML — Tree

XML Tree Structure

<bookstore>
    <book>
        <title>Harry Potter</title>
        <author>J.K. Rowling</author>
    </book>
    <book>
        <title>Learning XML</title>
        <author>Erik T. Ray</author>
    </book>
</bookstore>

Tree Concepts

Term	Description
Root	Top-level element
Parent	Element containing children
Child	Element inside a parent
Sibling	Elements at same level
Leaf	Element with no children

Tree Traversal

bookstore (root)
├── book (child)
│   ├── title (leaf)
│   └── author (leaf)
└── book (child)
    ├── title (leaf)
    └── author (leaf)

Navigating the Tree

• Parent: Go up one level
• Children: Go down one level
• Siblings: Go left or right
• Ancestors: Go up multiple levels
• Descendants: Go down multiple levels

XPath Navigation

/bookstore/book[1]          # First book
/bookstore/book/title       # All titles
//book[@genre='fiction']     # Fiction books
/bookstore/book[last()]     # Last book

Mini Practice

1. Draw a tree for an XML document
2. Identify parent, child, sibling relationships
3. Write XPath expressions
4. Navigate from root to leaf

Up Next

Continue with DOM — Document Object Model for XML.