Ahlul Hadith or Ahlul Ray [ أهل الحديث و أهل الرأي]?

What is the difference between Ahlul Hadith(People of Hadith) and Ahlul Rai(People of opinion) from fiqh perspective in the sense how do they differ in ruling? , I read that Hanafi Madhab is the only school which subscribes to Ahlul Rai is that true? and how is such an AhlulRay madhab different from the Ahlul Hadith Madhabs like Shaafi, Hanbali, Salafi etc, in the manner of deriving rulings?