Final answer:
The answer to which is not an advantage of database systems is data redundancy, as it leads to unnecessary duplication and potential inconsistencies in a database, opposed to data independence, security, and abstraction which are advantages. option a is the correct answer.
Step-by-step explanation:
The student asked which of these is not an advantage of database systems. The options provided are:
- Data redundancy
- Data independence
- Data security
- Data abstraction
The correct answer to this question is data redundancy. Data redundancy refers to the unnecessary duplication of data within a database, which is generally not considered an advantage since it can lead to inconsistencies and increased storage costs. On the other hand, data independence, data security, and data abstraction are all advantages of using a database system. Data independence allows for changes to the data structure without affecting the application logic. Data security ensures that the data is protected from unauthorized access or alterations. Data abstraction allows users to interact with the database without needing to know the underlying complexities.