Database Schema Comparison is a common technique used to identify data consistency issues in databases. It involves comparing the structure and contents of databases, such as tables, views, and relationships, to ensure consistency and accuracy across different database instances.

Hashing algorithms are commonly employed in data integrity testing to ensure the consistency and accuracy of data by generating fixed-size hash values for comparison.

Authorization testing concentrates on assessing the adequacy and accuracy of access control policies. Access control policies define who can access what resources under what conditions. Therefore, authorization testing primarily involves ensuring that the access control mechanisms are correctly implemented and enforced to prevent unauthorized access to sensitive data or functionalities. User identification is related to authentication, whereas data integrity is more concerned with data quality and accuracy.

"Alerting" in database monitoring refers to the functionality where monitoring tools notify administrators about critical events or conditions that require attention. These alerts can be configured based on predefined thresholds for metrics such as CPU usage, memory consumption, disk space, or query response time. Timely alerts enable proactive management, allowing administrators to address issues promptly and ensure uninterrupted database operation.

Functional validation ensures that data conforms to predefined rules and constraints. It checks if the data meets the expected criteria regarding its format, range, and relationships, ensuring data integrity and consistency.

Data encryption commonly utilizes symmetric or asymmetric algorithms to convert sensitive information into an unreadable format. Hashing algorithms are commonly used for ensuring data integrity, not encryption. Compression algorithms reduce the size of data but do not encrypt it.

Profiling tools are crucial for identifying performance bottlenecks within a database system. These tools analyze various aspects such as query execution times, resource consumption, and system waits, helping database administrators pinpoint areas that require optimization to enhance overall performance.

The SQL GROUP BY clause is used to group rows that have the same values into summary rows, such as "find the number of customers in each city" or "calculate the total sales for each product category." It is typically used with aggregate functions (like COUNT, SUM, AVG, etc.) to perform calculations on each group of data. This clause helps in analyzing data by organizing it into manageable chunks based on specified criteria.

Referential integrity constraint ensures that a foreign key in one table references a primary key in another table. It maintains the consistency and integrity of the data by enforcing relationships between tables. This constraint prevents actions that would violate these relationships, such as deleting a record with a referenced foreign key.

A rollback plan is crucial in data migration testing as it ensures that in case of any failures or issues during migration, the system can be reverted back to its previous state, minimizing risks and ensuring data integrity.