This bike was given by my uncle,who works in Shanghai.这句子是什么

This bike was given by my uncle,who works in Shanghai.这句子是什么样的定语从句?
This bike was given by my uncle,who works in Shanghai.这句子是限制性定语从句吗?语法书上把它和This bike was given by my uncle who works in Shanghai.连起来讲了,有点让人看不明白,愿高手赐教.
我想说，语法书上说，这两个句子意思不完全一样的。有逗号的句子隐含我只有一个叔叔，而没有逗号的句子隐含我不止有一个叔叔。