Could somebody tell is it good idea use varchar as PK. I mean is it less efficient or equal to int/uuid? In example: car VIN I want to use it as PK but I'm not sure as good it will be indexed or work as FK or maybe there is some pitfalls.

CodePudding user response：

It depends on which kind of data you are going to store.

In some cases (I would say in most cases) it is better to use integer-based primary keys:

• for instance, bigint needs only 8 bytes, varchar can require more space. For this reason, a varchar comparison is often more costly than a bigint comparison.
• while joining tables it would be more efficient to join them using integer-based values rather that strings
• an integer-based key as a unique key is more appropriate for table relations. For instance, if you are going to store this primary key in another tables as a separate column. Again, varchar will require more space in other table too (see p.1).

This post on stackexchange compares non-integer types of primary keys on a particular example.