What happens when DB engine runs out of numbers to use for primary keys?

Question

Since DBs do not reuse numbers of deleted records it is possible to run out of numbers, especially if you pick not really a big integer type for this column.
What would

Answer 1

It depends on your database, I believe in MS SqlServer, you simply cannot insert any new rows until you fix the problem. The last time I encountered it, we fixed the problem by reseeding the identity column to 1. That's obviously not a universal fix, but it was ok with our situation.