I'm not sure how everyone else does it, but just wanted to get some thoughts (and cleanup) on how I've been converting empty strings to null in an effort to make MySQL yell at the user.

I have a top level, abstract ModelObserver that does the following. I've stripped out all irrelevant code.

abstract class ModelObserver {

	public function saving($model)
	{
		$values = $model->attributesToArray();

		array_walk($values, function(&$value)
		{
			$value = $this->emptyToNull($value);
		});

		foreach($values as $attribute => $value)
		{
			$model->{$attribute} = $value;
		}
	}

	private function emptyToNull($string)
	{
		if (trim($string) === '')
			$string = null;

		return $string;
	}
}