Matthew Harman focused on enhancing data integrity within the hmcts/libragob-batch-jobs repository by addressing a critical bug in the batch-processing workflow. He implemented a foreign key safe housekeeping process using advanced SQL scripting and database management techniques, ensuring that records in the table_updates table were only deleted when their corresponding update_request_id existed in update_requests and was older than five days. This approach protected referential integrity, reduced runtime errors during data cleanup, and aligned with established data governance rules. Matthew’s targeted SQL changes improved batch reliability and maintainability, demonstrating a thoughtful application of database management principles in a production environment.