Hashing Technique in a Database

Hello Everyone, I want to know the hashing technique in Database? My last interview was not good and The interviewer asked me this question and I am not given the answer. I have researched about this and found hashing is used to index and retrieve items in a database because it is faster to find the item using the shorter hashed key than to find it using the original value. Is it the right information or not? because I gave same answer in my previous round but the recruiter wasn't happy. Can anyone database expert who suggest me some more relevant questions which are helpful to me for upcoming interviews?