You use a contained database named ContosoDb within a domain. You need to create a user who can log on to the ContosoDb database. You also need to ensure that you can port the database to different…

While a type of contained database user, creating a user mapped to a certificate involves managing certificates and does not directly leverage existing domain identities for simplified portability within a domain context.

A SQL user without login is a contained database user authenticated by a password stored within the database, which does not utilize Windows domain authentication or simplify portability for domain users across servers.

For a contained database, a Windows domain user can be added directly to the database without requiring a separate server-level login. This ensures that the user's authentication relies on the domain, making the database portable across different SQL Server instances within the same domain without needing to recreate or reconfigure server-level logins, thus fulfilling the portability requirement.

A SQL user with login requires a server-level login, which explicitly ties the user to a specific SQL Server instance and violates the requirement for a contained database that needs portability without additional server-level configurations.