Elefant provides a built-in version control mechanism for any Model object. It also provides a way of accessing, comparing, and restoring previous versions through the Tools > Versions menu option.
To add version control to your own models, whenever you update your model object simply call Versions::add() like this:
<?php
$obj = new MyModel ($some_id);
$obj->some_value = 'New value';
$obj->put ();
if (! $obj->error) {
// Save a new version of the changes
Versions::add ($obj);
// Proceed with successful save handling
}
?>
That's the same code you would use for creating new objects and updating them.
You can easily get the version history of any Model object, or the recent changes made by a given user, like this:
<?php
$obj = new MyModel ($some_id);
// Get the history of $obj
$history = Versions::history ($obj);
// Get recent changes made by $user
global $user;
$recent = Versions::recent ($user);
?>
The Versions class is itself a Model object, defined in apps/admin/models/Versions.php, and so it inherits all of the features of Model itself as well as its own add(), restore(), history(), recent(), and diff() methods.