Context: While there is typically only one conceptual (or logical) and physical (or internal) view of the data, there can be any number of different external views. This allows users to see database information in a more business-related way rather than from a technical, processing viewpoint. For example, a financial department of a company needs the payment details of all employees as part of the company's expenses, but does not need details about employees that are the interest of the human resources department. Thus different departments need different views of the company's database.

Question: How many conceptual or physical views of data are there?
Answer: one

Question: How many different external views of data are there?
Answer: any number

Question: What is the benefit of external views of data?
Answer: see database information in a more business-related way

Question: How many conceptual or physical views of data do not exist?
Answer: Unanswerable

Question: How many duplicated external views of data are there?
Answer: Unanswerable

Question: What is the disadvantage of external views of data?
Answer: Unanswerable

Question: Who is not allowed to see database information?
Answer: Unanswerable