Hi everyone,

I'm trying to design a database and I want to know what's the most efficient way to populate fields with referenced values.

I have the following database design:
Database.JPG

For the country table, my unique ID is not a number but rather an ISO two-letter country code, i.e. JP, US, DE, etc. This leads to my first question:
Q1) Is this an efficient approach, using a non-numerical ID, or is numerical ID's always the best?

For the vehicles table, I have the vehicleBrand field referencing the vehicleBrandID field of the vehicleBrands table. When I do this though of course, the dropdown to select what vehicleBrand entry is just a list of the vehicleBrands IDs, like so:
Database2.JPG

This leads me to my second question:
Is it best to use a numerical ID for internal database operations, and then when you generate some kind of view, i.e. a dropdown, add extra code to just populate those dropdown options with another field from that row

Thanks in advance!