At 10:37 the video starts talking about when not to use autonumbers. I have a question on this.

There ISO standards on country codes and how they are grouped by region and sub region (three tables)
The code for the USA is 840, and there are two and three character codes as well as a country name. I have no idea if the ISO org is going to change those codes, but if they did it would be chaos, as they are used in millions of applications.

So, do I use an autonumber for a table containing ISO code of 840 that has a description of United States of America (and US & USA)?  Or just make 840 the natural (and primary) id even though 840 isn't all that natural. I mean, I never say I'm from 840.

The same goes for languages. The ISO also has standards for languages, 182 last time I checked. Same thing "en" = English, "es" = Spanish. Use autonumbers or just the two digit ISO code?

Finally, in my app, I define the software modules. For example, PR = payroll, HR = human resources. The records aren't going to change or get deleted once created and used.

I guess I could use autonumbers for all these, but then I have to add the autonumbers to the existing table fields and then go change any records that used the old key. USA->840->240 (autonumber) after all this.

What are your thoughts on this after two days of reading?