This is obvious if you took a DB course, and if you didn't, you have no business building a DB. Sadly, all the NoSQL junkware was built by people who didn't.
The example is flawed -- if there is an exception incurred before or during the sending of the email, the operation will be erroneously marked as "cancelled" without having completed all of the cancellation flow. Namely, with the example as given, it is possible to have a cancelled order for which an email has not been sent out.
Moving the second line (the one that changes the status to "cancelled") to the end fixes this issue, though it does not implement "exactly once" semantics for the sending of the email. If "exactly once" is desirable, then additional logic is required. But in every case, the example as given is incorrect.
What a self-indulgent writeup. The article came nowhere near answering the central question: what are the devs doing other than constantly changing the name of the project and how is this thing better than gimp.
Good riddance to these tools because this technique, of relying on embedded strings in the code, is inherently insecure and unreliable. You can only really on it when you know you can trust the build, and yet they are used in cases where the build is of unknown etiology, so there's an inherent mismatch between when the tool is used and what it does.