For the longest time I’ve been really fascinated by what I call “socially relevant primary keys”. These are primary keys that take on a great deal of social meaning, over and above the requirements of any particular query or piece of code. Might be easiest to explain by way of example.

Here are the kinds of keys I have in mind:

  • Telephone area codes, which create a kind of regional affiliation for people who live in a major metropolitan area.
  • Zip codes, which function as kind of hyperlocal primary keys. There is of course the (in)famous 90210, which had a whole TV show dedicated to it, as well as 02138, home to two of the most pre-eminent universities in the world.
  • Airport codes, which again create a kind of regional affiliation. To my understanding people in Portland, OR think of themselves as residents of “PDX”.
  • Highway numbers, which create a sense of orientation more than regional affiliation. They also, strangely, create a feeling of history and momentum, as Highway 66 did in The Grapes of Wrath and the Lincoln Highway did in in the book by the same name.
  • Social security numbers, which were never meant to be personal identifiers but of course have morphed into that usage, for better or worse.

I find these examples of people latching on to somewhat arbitrary strings of letters and numbers to be pretty fascinating to me. They also carry a certain kind of story - primarily about mundane regulatory regimes, but also about the development of the modern world over time. I’d love to hear more examples and add to my collection!