Searching for a customer's information

In an earlier post I talked about my experiences with the telephone company.

Here is a little part of their system that may make sense to someone inside the company, but does not make a lot of sense to this customer.

If I was going to build a system to keep track of individual customer's information I would need a way to bring up customer's files. This should be some unique customer identifier.

The obvious ones that spring to mind are telephone number, name (perhaps in combination with birth date), or maybe address.

But no. How does my telephone company keep track of customer accounts? Driving License number.

What a bizarre way to do it.

One day someone will be able to explain it to me. I eagerly await that day.