The middle dot (·) in Chinese signals a foreign-name boundary.
德 (Dé) here renders the Dutch nobiliary particle 'de' (as also used in 'de Vries', 'de Gaulle');
海克 (Hǎikè) approximates a 'Heeck/Haeck' surname. The same
德 syllable handles 'de'/'di' in many European names.