If you're wrapping every call in `try/catch` or equivalent, then something's probably wrong in your invariants. If customer.phoneNumber is a non-null foreign-ke

If you're wrapping every call in `try/catch` or equivalent, then something's probably wrong in your invariants. If customer.phoneNumber is a non-null foreign-key, your application should safely be able to assume that Phone.findByNumber(customer.phoneNumber) will succeed. If you don't get to assume that, then you have business-logic errors elsewhere and your best bet is to crash.