In SQL, the terms "System User" and "Session User" refer to two different types of users, each serving distinct purposes. Here's the breakdown of the differences between them:
Scope: System users have access to the entire database system and can manage user accounts, system settings, perform backup tasks, manage storage, and more. Example: SYS, SYSTEM (Oracle) sa (SQL Server, for System Administrator) Privileges: System users often have high-level privileges like the ability to create, alter, or drop databases, change system-wide configurations, and assign user permissions. Persistence: The user account is persistent and exists as long as the database instance is running, and it can be accessed by administrators and certain applications whenever needed.
Scope: A session user is specific to their active connection (session) to the database and does not have access to the entire system. They can only access the resources and data they are authorized to view or modify. Example: A user logging into the database as user1, employee1, etc. Privileges: Session users have a set of permissions defined by the database administrator (DBA) and are restricted to only the actions they are allowed to perform (e.g., SELECT, INSERT, UPDATE, DELETE). Persistence: A session user is only active during the duration of their connection to the database. Once the session ends (e.g., when they log out or the session expires), the user is no longer active.