Developed cross-database upsert functionality for the typeorm/typeorm repository, enabling MERGE-like operations across Oracle, SQL Server, and SAP HANA. This work involved enhancing the query builder to support upsert semantics, allowing developers to perform insert or update actions without resorting to ad-hoc SQL. The implementation included comprehensive documentation and tests to ensure consistent behavior and reliability across supported databases. Utilizing TypeScript and JavaScript, the developer focused on backend development and database integration, expanding ORM capabilities. The feature broadens compatibility for enterprise databases and streamlines data management workflows, reducing the need for custom upsert logic in application codebases.