ServiceNow Studio is used to develop and manage application artifacts within a scoped application, including server-side logic that runs when database operations occur. “Customizing system behavior through database actions” points directly to server-side automation triggered by record operations such as insert, update, delete, and query. The platform feature designed for that purpose is Business Rules, which execute on the server in response to database events and can validate data, set field values, enforce policies, or initiate additional processing. While Studio can also include other file types such as Client Scripts, UI Policies, and ACLs, those are not primarily described as “database actions.” Client Scripts and UI Policies are primarily UI and client behavior controls, and ACLs control security access. Business Rules are the canonical mechanism for database-triggered behavior and are the best match to the question’s wording. Therefore, the file type aligned to customizing system behavior through database actions is Business Rules (sys_script).