Continuing the discussion from the previous subsection, we once again look at the database structure for Book Someplace, Inc. Another issue with the embedded document approach is what happens when the original customer document is updated? Now you have two places where customer information is stored: once in the customers collection, another in the bookings collection. The solution to this problem depends on the company's philosophy with regard to bookings. On the one hand, you could argue that at the time of the booking the customer information was correct, and must be maintained as is for historic reasons. On the other hand, you could argue that the latest information should always be present in bookings regardless of the situation that existed at the time of the booking. In the latter case, following a customer update, you would need to perform a series of secondary updates on all relevant bookings.
Returning to the BigLittle Micro Finance...