This is in case somebody gains unauthorised access to the data, not in case staff can't be trusted. For example, paying by credit card over the phone you hand over your phone number to whoever is taking your order, but if they were to enter it into a system that system then has to comply with regulations.
Not exactly. The purpose is to limit the number of people who have access to your credit card number so that if one of them uses it fraudulently, it's easy to isolate and verify the source of the fraudulent transactions. Yes, the guy taking the order over the phone will have access to your credit card number. Yes the waiter running your card at the restaurant will have access to your credit card number. If the system is well designed, though, no one else will, and it'll be easy to find the person to blame if fraudulent transactions are made.
I've never worked on PCI compliant systems myself, but I know many developers who have, and they say that the sysadmins take solid measures to ensure that no one, not even the developers, gets any data from a database that handles credit card information. Any data pulled from those servers is first sanitized to ensure that credit card numbers and other personally identifying information is removed. Credit card numbers are replaced with a "sample" number that can be used for validation purposes. Names other information are replaced with sanitized data that has the same "shape" (e.g. number of characters and identical punctuation) as the original.
The purpose of these regulations is to ensure that there's always a clear chain of custody over your credit card numbers. Preventing unauthorized access is only one part of maintaining that chain of custody.
Not exactly. The purpose is to limit the number of people who have access to your credit card number so that if one of them uses it fraudulently, it's easy to isolate and verify the source of the fraudulent transactions. Yes, the guy taking the order over the phone will have access to your credit card number. Yes the waiter running your card at the restaurant will have access to your credit card number. If the system is well designed, though, no one else will, and it'll be easy to find the person to blame if fraudulent transactions are made.
I've never worked on PCI compliant systems myself, but I know many developers who have, and they say that the sysadmins take solid measures to ensure that no one, not even the developers, gets any data from a database that handles credit card information. Any data pulled from those servers is first sanitized to ensure that credit card numbers and other personally identifying information is removed. Credit card numbers are replaced with a "sample" number that can be used for validation purposes. Names other information are replaced with sanitized data that has the same "shape" (e.g. number of characters and identical punctuation) as the original.
The purpose of these regulations is to ensure that there's always a clear chain of custody over your credit card numbers. Preventing unauthorized access is only one part of maintaining that chain of custody.