To answer this question, you need to understand the concept of database design features and their impact on SQL performance.
Option A) Removal of data redundancy - This option is incorrect because removing data redundancy is a good practice in database design to improve data integrity and reduce storage space. However, it does not directly impact SQL performance.
Option B) The introduction of data redundancy - This option is correct because introducing data redundancy can improve SQL performance in certain scenarios. By duplicating data across multiple tables, it can eliminate the need for complex join operations and improve query performance. However, it is important to note that data redundancy should be used judiciously and carefully managed to ensure data consistency and integrity.
Option C) The introduction of non-first normal form relations - This option is incorrect. Normalization is a process in database design that helps eliminate data redundancy and improve data integrity. However, introducing non-first normal form relations can lead to more complex queries and potentially slower SQL performance.
Option D) The introduction of SQL*Plus - This option is incorrect. SQL*Plus is a command-line interface tool for SQL, but it does not directly impact database design features or SQL performance.
Therefore, the correct answer is B) The introduction of data redundancy. This option is correct because introducing data redundancy can improve SQL performance in certain scenarios by reducing the need for complex join operations.