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by marcosdumay 534 days ago
There's something very, very wrong in the way we write programs nowadays.

Because yeah, the database is you main source of invariants. But there is no good reason for you application environment not to query the invariants from there and test or prove your code around them.

We do DRY very badly, and the most vocal proponents are the worst... But I don't think this is a good example of the principle failing.
2 comments
nrr 533 days ago
> There's something very, very wrong in the way we write programs nowadays.

I largely agree, but...

> ... the database is you main source of invariants.

I guess my upbringing through strict typing discipline leaves me questioning this in particular. I'm able to encode these things in my types without consulting my database at build time and statically verify that my data are as they should be as they traverse my system with not really any extra ceremony.

Encoding that in the database is nice (and necessary), but in the interest of limiting network round-trips (particularly in our cloud-oriented world), I really would prefer that my app can get its act together first before crossing the machine boundary.

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jcgrillo 534 days ago
> no good reason for you application environment not to query the invariants from there and test or prove your code around them

As a developer who primarily builds backend web applications in high level languages like golang and java I run the risk of sounding ignorant talking like this but.. I'm led to believe lower level systems and embedded software has a lot more invariant preserving runtime asserts and such in it. The idea being that if an invariant is violated better to fail hard and fast than to attempt to proceed as if everything is alright.

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marcosdumay 533 days ago
Hum... I'm not sure we are talking about the same thing. Of course system and embedded software won't have invariants stored in a database, the comment isn't about them.

But, there isn't a faster way to fail to an invariant than to prove statically that your code fails it, or to test it before deploying. I don't really understand your criticism.

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