Over a two-month period, contributed backend enhancements to cap-js/cds-dbs and SAP-samples/cap-sflight, focusing on database optimization and concurrency control. Improved HANA SQL generation by sorting columns and expanding queries before formatting, which reduced execution plan regenerations and improved runtime latency. Introduced an INSERT_SELECT method for safer data ingestion with explicit column mapping. In SAP-samples/cap-sflight, implemented centralized travel draft locking and unified accept/reject workflows, enhancing data integrity and user experience during concurrent modifications. Leveraged Java, TypeScript, and SQL to deliver maintainable, low-risk features that improved performance, reliability, and code quality across both repositories without introducing new bugs.