This is a good story and something everyone should experience in their career even just for the lesson in humility. That said:
> Here's the technical takeaway: Never use CASCADE deletes on critical foreign keys. Set them to NULL or use soft deletes instead. It's fine for UPDATE operations, but it's too dangerous for DELETE ones. The convenience of automatic cleanup isn't worth the existential risk of chain reactions.
What? The point of cascading foreign keys is referential integrity. If you just leave dangling references everywhere your data will either be horribly dirty or require inconsistent manual cleanup.
As I'm sure others have said: just use a test/staging environment. It isn't hard to set up even if you are in startup mode.
> Here's the technical takeaway: Never use CASCADE deletes on critical foreign keys. Set them to NULL or use soft deletes instead. It's fine for UPDATE operations, but it's too dangerous for DELETE ones. The convenience of automatic cleanup isn't worth the existential risk of chain reactions.
What? The point of cascading foreign keys is referential integrity. If you just leave dangling references everywhere your data will either be horribly dirty or require inconsistent manual cleanup.
As I'm sure others have said: just use a test/staging environment. It isn't hard to set up even if you are in startup mode.