During January 2025, Donghwan Kim developed two in-depth documentation features for the SYSOUT-org/CS-Study repository, focusing on database transactions and normalization. He consolidated complex concepts such as ACID properties, isolation levels, and transaction anomalies, providing clear guidance on MySQL and Spring transaction management. Using Markdown, Donghwan structured the documentation to support developer onboarding and reduce support overhead, ensuring alignment with repository standards. His work demonstrated a strong grasp of database theory and practical documentation, covering normal forms, denormalization, and performance considerations. The resulting documentation improved maintainability and knowledge transfer for developers working with relational databases and transactional systems.