Comment by jchw

In addition to the sibling comment, which is exactly right (you should be using a nullable column here, if you're using SQL, for multiple reasons) I reckon this a design issue in the programming language that is largely unrelated to how you model the database. It's pretty easy to run into bugs especially if you compound it with other quirky APIs, like strcmp: `if (strcmp(a, b)) // forgot to do == 0; accidentally backwards!` -- So really, you just don't have much of a choice other than to tread carefully and enable compiler warnings. Personally in this case I'd use an Optional wrapper around the underlying timestamp type anyways, if I needed to be able to represent the UNIX timestamp at 0 as well as an empty state.