You're developing a customer loyalty app for a small chain of retail stores. The app will need a backend database to maintain customer information. While designing the app, you're conducting a planning meeting with your client to determine the scope of the project and resolve questions she has about the project.

Client:

I$\text{'}$m trying to understand how all this will work$$how the app and the database will work together. Where will you get the information for the database?

You:

This data is specific to your company, so it's called

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data. Your customers will enter their personal information when they create their accounts. Then sales transactions will continue to add data about each customer over time.

Client:

That sounds like a lot of data. Won't the database get too big to find information quickly?

You:

Good question. We can build in a$($n$)$

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or two to help speed up queries. It will take up a bit more space, but will greatly increase efficiency for user interactions.

Client:

I suppose "users" include customers and employees. Will they all see the same information about each account?

You:

No$,$ we'll design separate

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for each type of user so the user gets exactly the needed information and nothing more. This is especially important when considering customer privacy.