Security Levels

A user passes through two stages of security when working in Microsoft® SQL Server™: authentication and authorization (permissions validation).The authentication stage identifies the user using a login account and verifies only the ability to connect to an instance of SQL Server. If authentication is successful, the user connects to an instance of SQL Server. The user then needs permissions to access databases on the server, which is done by granting access to an account in each database, mapped to the user login. The permissions validation stage controls the activities the user is allowed to perform in the SQL Server database.