Which of the following are considered non-schema objects?

Users and roles are classified as non-schema objects because they manage permissions and access control within a database rather than directly storing data or defining the organization of data. In database management systems, non-schema objects pertain to security and user management functionalities, enabling administrators to set up user accounts, assign roles, and determine which database entities users can access.

In contrast, other options such as tables, indexes, views, procedures, data types, and triggers directly relate to the schema of the database. They define the structure of the data and how it can be utilized, indicating that they are integral to the organization and manipulation of the data itself. Understanding this distinction helps in effectively managing database systems, particularly around user privileges and data integrity.