Data compression techniques in database systems primarily aim to reduce storage space and improve data transfer speed. By compressing data, the amount of disk space required to store large datasets is reduced, which can lead to cost savings and improved performance. Additionally, compressed data can be transmitted more quickly over networks, making data transfer more efficient.

Enforcing referential constraints ensures that relationships between tables are maintained, preventing actions that would compromise the consistency and integrity of the data. These constraints typically involve foreign keys linking records in different tables.

A test dashboard serves as a centralized platform that provides real-time updates on various testing metrics and key performance indicators. It offers stakeholders a visual representation of the testing progress, including test execution status, defect trends, and coverage metrics. By displaying critical information in an easy-to-understand format, a test dashboard enables stakeholders to quickly assess the health of the project and make data-driven decisions. It enhances communication and collaboration among team members and helps in identifying potential risks or bottlenecks early in the testing process.

Error handling in SQL queries is crucial for gracefully managing unexpected situations or errors that may occur during query execution. It allows developers to anticipate potential issues and implement mechanisms to handle them, ensuring the reliability and robustness of the database application.

Audit trails in database security serve the purpose of monitoring and recording various activities performed within the database. This includes tracking user logins, data modifications, and access attempts. By maintaining an audit trail, organizations can analyze and review the history of database operations for security and compliance purposes, identifying any suspicious or unauthorized activities.

Role-Based Access Control (RBAC) is a method of access control that restricts access to resources based on the roles of individual users within an organization. It ensures that only authorized users are able to access certain resources based on their assigned roles, minimizing the risk of unauthorized access. RBAC is widely used in database security to enforce strict access control policies.

In ETL process testing, dealing with massive data volumes is a prevalent challenge, requiring efficient testing strategies to ensure scalability, performance, and accuracy of data processing.

Indexing plays a crucial role in enhancing the performance of data retrieval operations by enabling the database system to locate and access the required data more efficiently. It organizes the data in a structured format, reducing the time taken to search through large datasets. Thus, indexing contributes to better performance in terms of query execution speed and response time.

Key rotation is a crucial key management technique for ensuring the security of encrypted data in a database. It involves periodically changing encryption keys used to encrypt data, which helps mitigate the risk associated with compromised or outdated keys. By regularly rotating keys, organizations can enhance security and reduce the window of vulnerability to potential attacks. Proper key rotation strategies should balance security requirements with operational efficiency to ensure smooth functioning of the database system. Therefore, option 1 is the correct choice.

In ETL processes, data transformation ensures that data conforms to predefined business rules, which is a critical aspect of data validation. Transformation validation verifies that the data has been transformed correctly according to the specified business rules and requirements.