books.xml

<?xml version="1.0"?>
<x:books xmlns:x="urn:books">
   <book id="1">
      <author>Writer</author>
      <title>The First Book</title>
      <genre>Fiction</genre>
      <price>44.95</price>
      <pub_date>2000-10-01</pub_date>
      <review>An amazing story of nothing.</review>
   </book>
</x:books>

books.xsd

<xsd:schema xmlns:xsd="http://www.w3.org/2001/XMLSchema"
            targetNamespace="urn:books"
            xmlns:bks="urn:books">

  <xsd:element name="books" type="bks:BooksForm"/>

  <xsd:complexType name="BooksForm">
    <xsd:sequence>
      <xsd:element name="book" 
                  type="bks:BookForm" 
                  minOccurs="0" 
                  maxOccurs="unbounded"/>
      </xsd:sequence>
  </xsd:complexType>

  <xsd:complexType name="BookForm">
    <xsd:sequence>
      <xsd:element name="author"   type="xsd:string"/>
      <xsd:element name="title"    type="xsd:string"/>
      <xsd:element name="genre"    type="xsd:string"/>
      <xsd:element name="price"    type="xsd:float" />
      <xsd:element name="pub_date" type="xsd:date" />
      <xsd:element name="review"   type="xsd:string"/>
    </xsd:sequence>
    <xsd:attribute name="id"   type="xsd:positiveInteger"/>
  </xsd:complexType>
</xsd:schema>

test.php

<?php

$xmlfile = __DIR__ . DIRECTORY_SEPARATOR . 'books.xml';
$xsdfile = __DIR__ . DIRECTORY_SEPARATOR . 'books.xsd';

$xml = new XMLReader();
if(!$xml->open($xmlfile, null, LIBXML_PARSEHUGE)){
  logging('Unable to Open XML file (Full Parse 1):' . $xmlfile);
  return false;
}
$xml->setSchema($xsdfile);
while($xml->read()){
}