The IBM C2090-623 exam is a comprehensive assessment designed to evaluate your expertise in working with IBM DB2 12 for z/OS. This exam covers a wide range of topics, including the architecture and components of DB2, such as the database manager, buffer pool, and storage groups. You'll delve into the intricacies of SQL processing, learning about the optimizer, query execution, and how to optimize performance. The exam also focuses on data administration, covering topics like database design, data modeling, and the management of database objects. Additionally, you'll explore data recovery and high availability, learning about backup and recovery techniques, and implementing strategies for ensuring data integrity and system availability. Security is a key aspect, with a focus on user and data security, as well as implementing security measures. The exam also touches on performance monitoring and tuning, teaching you how to analyze and improve DB2 performance. Finally, you'll learn about utilities and tools, including the DB2 Command Line Processor and the DB2 Control Center, and how to utilize them effectively. These topics provide a deep understanding of DB2 12 for z/OS, ensuring you're equipped with the knowledge to manage and optimize database systems efficiently.