A single Knowledge Base (KB) or Knowledge Base Article in ServiceNow can have an unlimited number of User Criteria Records applied to it. This flexibility allows for comprehensive and detailed user access control, ensuring that the right information is accessible to the appropriate users based on various criteria.

In the base ServiceNow instance, User Criteria are used to control read and write access to Knowledge bases and articles. This ensures that only users who meet specific criteria can access, read, or edit particular knowledge content, helping to manage information access and maintain security.

Both the User table and the HR Profile table are required for an HR application. The User table (sys_user) stores fundamental user information, which is essential for managing user-related activities and permissions. The HR Profile table (sn_hr_core.profile) stores specific HR-related details about each user, necessary for handling HR processes and records. Thus, to fully function in an HR context, both tables are required.

In the base instance, Matching Rules determine the conditions a Case must meet before it can be assigned to an agent. Matching Rules evaluate criteria and attributes to find the most suitable agent or group for the Case assignment, ensuring efficient and relevant handling of tasks.

The required role to view confidential HR Profile data is HR Admin [sn_hr_core.admin]. This role encompasses the necessary permissions to access sensitive and confidential HR information, ensuring a higher level of security and access control. The HR Basic role is typically more limited in scope and does not include access to confidential data, while the HR Manager and LE Admin roles do not specifically grant the necessary permissions for HR Profile data.