Relational database design question - Surrogate-key or Natural-key?

Question

Which one is the best practice and Why?

a) Type Table, Surrogate/Artificial Key

Foreign key is from user.type to type.i

Answer 1

well i think surrgote key is helpful when you don't have any uniquely identified key whose value is related and meaningful as is to be its primary key... moreover surrgote key is easier to implement and less overhead to maintain.

but on the other hand surrgote key is sometimes make extra cost by joining tables. think about 'User' ... I have

UserId varchar(20), ID int, Name varchar(200)

as the table structure.

now consider that i want to take a track on many tables as who is inserting records... if i use Id as a primary key, then [1,2,3,4,5..] etc will be in foreign tables and whenever i need to know who is inserting data i've to join User Table with it because 1,2,3,4,5,6 is meaningless. but if i use UserId as a primary key which is uniquely identified then on other foreign tables [john, annie, nadia, linda123] etc will be saved which is sometimes easily distinguishable and meaningful . so i need not to join user table everytime when i do query.

but mind it, it takes some extra physical space as varchar is saved in foreign tables which takes extra bytes.. and ofcourse indexing has a significant performance issue where int performs better rather than varchar