> obvious things like ATM withdrawals aren’t allowed I don't know if it's still common to run things this way, but I've worked for a few banks where the core d

> obvious things like ATM withdrawals aren’t allowed I don't know if it's still common to run things this way, but I've worked for a few banks where the core database stopped running all OLTP for a short period every day for tasks like settlement and interest calculations, etc.. During that time they'd still allow ATM withdrawals, and if you knew the schedule it was possible to go into an unapproved overdraft.