数据库系统基础教程答案与示例分析

The exercise provided in the "Database Systems Fundamentals Tutorial Answers.pdf" discusses the concept of functional dependencies (FDs) and possible keys in a database system. Answers for this exercise may vary depending on different interpretations. Some possible functional dependencies mentioned in the exercise are Social Security number → name, Area code → state, and Street address, city, state → zipcode. These dependencies illustrate how certain attributes in a database are functionally dependent on each other. Possible keys mentioned in the exercise include {Social Security number, street address, city, state, area code, phone number}. This key is necessary to uniquely identify each record in the database. It is highlighted that the street address, city, state are needed to determine the location of an individual, as a person could have multiple addresses. The same applies to phone numbers, as individuals could have both a landline and a cellular phone number. In conclusion, this exercise emphasizes the importance of identifying functional dependencies and keys in a database system to ensure data integrity and uniqueness. It highlights the complexities that can arise when dealing with multiple attributes and the need to carefully design the database schema to accurately represent the relationships between data entities.