protected function setPart($part, $sql, $bind = false)
	{
		$this->parts[$part] = $sql;
		
		if (is_array($bind)) 		$this->bind[$part] = $bind;
		else if ($bind === false)	$this->bind[$part] = false;
		else						$this->bind[$part] = [$bind];
		
		return $this;
	}