A tourist arrives in Sydney, Australia on a leisure trip. They are looking to visit Tasmania by sea, by taking the ferry. There are different ports for departure/arrival. Consider the transaction where this tourist (now customer) wants to book a ferry that goes from port A to port B on a given date and time. 

2. Explain the steps that are needed in order to update the database when a customer books this ferry. *Should explain it step-by-step
4. Assuming that multiple customers can access the booking system from different locations. Describe (briefly) the major issue(s) that may arise in this situation.