<table name="wiki_page">
  <column name="id" required="true" primaryKey="true" autoIncrement="true" type="INTEGER" />
  <column name="title" type="VARCHAR" required="true" />
  <column name="body" type="LONGVARCHAR" />
  <behavior name="versionable" />
</table>

$page = new WikiPage();

// automatic version increment
$page->setTitle('Propel');
$page->setBody('Propel is a CRM built in PHP');
$page->save(); 
echo $page->getVersion(); // 1
$page->setBody('Propel is an ORM built in PHP5');
$page->save();
echo $page->getVersion(); // 2

// reverting to a previous version
$page->toVersion(1);
echo $page->getBody(); // 'Propel is a CRM built in PHP'
// saving a previous version creates a new one
$page->save();
echo $page->getVersion(); // 3

// checking differences between versions
print_r($page->compareVersions(1, 2));
// array(
//   'Body' => array(
//      1 => 'Propel is a CRM built in PHP',
//      2 => 'Propel is an ORM built in PHP5'
//    ),
// );

// deleting an object also deletes all its versions
$page->delete();

$page = new WikiPage();
$page->setTitle('PEAR');
$page->setBody('PEAR is a framework and distribution system for reusable PHP components');
$page->setVersionCreatedBy('John Doe');
$page->setVersionComment('First draft');
$page->save();
// do more modifications...

// list all modifications
foreach ($page->getAllVersions() as $pageVersion) {
  echo sprintf("'%s', Version %d, updated by %s on %s (%s)\n",
    $pageVersion->getTitle(),
    $pageVersion->getVersion(),
    $pageVersion->getVersionCreatedBy(),
    $pageVersion->getVersionCreatedAt(),
    $pageVersion->getVersionComment(),
  );
}
// 'PEAR', Version 1, updated by John Doe on 2010-12-21 22:53:02 (First draft)
// 'PEAR', Version 2, updated by ...

$category = new Category();
$category->setName('Libraries');
$page = new WikiPage();
$page->setTitle('PEAR');
$page->setBody('PEAR is a framework and distribution system for reusable PHP components');
$page->setCategory($category);
$page->save(); // version 1

$page->setTitle('PEAR - PHP Extension and Application Repository');
$page->save(); // version 2

$category->setName('PHP Libraries');
$page->save(); // version 3

$page->toVersion(1);
echo $page->getTitle(); // 'PEAR'
echo $page->getCategory()->getName(); // 'Libraries'
$page->toVersion(3);
echo $page->getTitle(); // 'PEAR - PHP Extension and Application Repository'
echo $page->getCategory()->getName(); // 'PHP Libraries'