Incremental data migration involves migrating only the partial data that has been modified since the last migration, reducing the workload and minimizing disruption to the system.

Data profiling involves analyzing data to understand its structure, content, and quality. It helps in identifying anomalies, such as inconsistencies, outliers, and discrepancies, which can affect data quality. Therefore, the correct option is "Anomalies."

A subquery in SQL, also known as a nested query or inner query, is a query nested within another SQL query. It is enclosed within parentheses and is executed first before the outer query. Subqueries are often used to retrieve data based on a condition or calculation from another table.

Data profiling in SQL query testing involves analyzing the characteristics and quality of the data involved in query operations. It helps identify patterns, anomalies, and inconsistencies within the data, thereby providing insights into its quality and completeness. By understanding the data better through profiling, testers can anticipate potential issues that may arise during query execution, such as data discrepancies or unexpected results. This proactive approach enables them to address these issues effectively, ensuring the reliability and accuracy of SQL queries in accessing and manipulating data.

One of the challenges in continuous integration for database testing is managing and versioning database schemas. As the database schema evolves with application changes, ensuring consistency and compatibility across different versions becomes crucial to maintain the integrity of the data and the functionality of the application.

QuerySurge

Load testing tools are specifically designed to simulate a high volume of concurrent users accessing the system. This type of testing helps assess the system's ability to handle increased loads and ensures its scalability under heavy usage conditions. Stress testing also evaluates system performance under extreme conditions, but it may not necessarily focus solely on simulating concurrent users.

Manually deleting affected rows is not a recommended approach as it might lead to data inconsistency. Restarting the SQL Server service is a drastic measure and may disrupt other ongoing operations. Executing a new COMMIT TRANSACTION statement would finalize the changes, which is contrary to the goal of rolling back. The correct step is to use the ROLLBACK TRANSACTION statement to undo the changes made so far and maintain data integrity.

Access control testing involves assessing the methods used to authenticate users and enforce authorization policies. Therefore, the correct option is "Authorization," as it pertains to defining and enforcing access rights. Authentication verifies the identity of users, encryption secures data during transmission or storage, and firewalls protect networks from unauthorized access but are not directly related to access control testing.

This suggests a data integrity issue. Data integrity ensures the accuracy, reliability, and consistency of data throughout its lifecycle. In this scenario, the presence of duplicate records in the target database that were not in the source data indicates a failure in maintaining the integrity of the data during the ETL process.