Where database blog posts get flame-broiled to perfection
Alright, settle down, kids. Let me put on my reading glasses... ah, yes. Well, isn't this just a delightful little piece of modern art? I have to hand it to you, reading this was a real trip down memory lane. It's truly inspiring to see you've all managed to solve a problem we hammered out on a System/370 back when "the cloud" was just something that caused rain.
I must commend your atomic, document-level operations. Truly a breakthrough. It's so... elegant. You take a business rule, translate it into what looks like a tax form designed by a committee, and embed it directly into the update statement. It reminds me of my first encounter with JCL in '83. You'd spend a week crafting the perfect job card, feed the deck into the reader, and pray to the silicon gods that you didn't misplace a single comma, lest you spend the next day sifting through a mountain of core dump printouts. Your $expr block gives me that same warm, fuzzy feeling of imminent, catastrophic failure. It's just so much simpler than, you know, a transaction.
And this whole function, goOffCall... bravo. Absolutely stunning. You've managed to write a query that checks a condition and performs a write in a single, unreadable blob. We used to do something similar in DB2, circa 1985. We called it a WHERE clause with a subquery. Didn't have all your fancy dollar signs and brackets, of course. We had to use plain English words like EXISTS and COUNT. It was terribly primitive, I know. You've clearly improved upon it by making it look like my cat walked across the keyboard.
Since MongoDB lacks explicit locking and a serializable isolation level, we can instead use a simple update...
Simple. You keep using that word. I do not think it means what you think it means. Back in my day, we had to manage our own locks because the system was too busy swapping punch cards. You kids have it so easy you've decided to pretend locking doesn't exist and call it "optimistic concurrency." We called that "two people overwriting each other's work and then blaming the night shift." Your "First Updater Wins" rule is adorable. It's like a participation trophy for race conditions.
I'm especially fond of this "document model" approach. You've put the list of doctors inside the shift document. It's a revolutionary concept known as "denormalization." We tried that in the late '70s with IMS databases. It was all fun and games until you needed to run a report on which doctors worked the most shifts across the whole year. The COBOL program to unwind that hierarchical mess took three days to write and an hour to run. We invented normalization for a reason, you know. But I'm sure your flexible indexing on fields inside embedded arrays completely solves that. Completely.
And the schema validation! My sides are splitting. Let me get this straight:
So, the database does all the work of finding the document, puts a pin in it, and only then decides the update is invalid. That's not a safeguard; that's a performance review meeting where you get fired after you've already completed the project. We used to have things called CHECK constraints. They were checked before the work was done. What a novel idea.
Honestly, this is all very impressive. You've built an entire ecosystem to avoid writing a simple BEGIN TRANSACTION; SELECT ... FOR UPDATE; UPDATE ...; COMMIT;. You've traded battle-tested, forty-year-old principles of data integrity for a query that requires a cryptographer to debug. You're running a "fuzz test" in a while(true) loop to prove your data integrity holds, which is the modern equivalent of me kicking the tape library to see if any of the cartridges fall out. They usually did.
But don't mind me. I'm just an old relic. You kids keep innovating. Keep embedding your business logic deep in the data layer where no one can find it. It's bold. It's exciting. And in about five years, you'll be writing another blog post about the revolutionary new "relational model" you've discovered to fix it all.
Keep at it, champ. You're doing great. Now if you'll excuse me, I have to go rewind some tapes.