The interviewer only asked me five questions and the interview was over

2022 year 2 month 26 Japan , Today is an unforgettable day for me ！ I just attended a meeting today Java interview , The interviewer asked some basic interview questions . for example , Overload override differences , Set related , But even so, I was puzzled by a problem .

interviewer Ask me ： Do you know the difference between database primary key and index ？

I The first reaction to this question is ：？？？ It's covered up , What's the difference between the two . Why did you take it “ Primary key ” Compare it with the index ？ There is a difference of 18000 miles ？ Or do I have other blind spots ？ These doubts are all surging up in my heart , There is no time for me to think , I can only answer .
Then I replied ：“ Primary key ” I don't know much about this concept , All I know is that indexing can be done much faster Retrieval speed of data , You can search according to the index tree when querying the database .
After I answer , I haven't lost my mind yet , The interviewer announced that the interview was over .

After the event , I talked with my friend about the interview experience , I told him I couldn't answer a question , Then I asked him ： database “ Primary key ” And index ？
He said it was not easy ？ A primary key is a unique identifier for each row of data , It can't be repeated , Must be unique .

After hearing this, I had an epiphany ： I opened my mouth to the quintessence of Chinese culture , It turned out to be a primary key ！！！ It's not a component . Let me just say why we compare components and indexes , This is not logical at all .

To make a long story short , I'm a Han Han . Stop talking and go on .