Understanding SQL Server Orphaned Users

Hello Dev, welcome to this article where we will explore the concept of SQL Server orphaned users. If you are a database administrator or a developer, you must have come across this term numerous times. SQL Server orphaned users are database users without any corresponding login in the SQL Server instance. These users become disconnected from their login and are unable to access the database. In this article, we will cover everything you need to know about orphaned users and how to fix them.

What are SQL Server Orphaned Users?

SQL Server orphaned users are database users who are disconnected from their corresponding login in the SQL Server instance. This happens when the login associated with a database user is deleted, and the user is not mapped to any other login. When this occurs, the user becomes an orphan and loses access to the database.

It is important to note that orphaned users do not pose any security risks to the database. They cannot access the database or any data within it. However, they do take up space in the database and can cause issues when migrating databases or restoring backups.

How Do Orphaned Users Occur?

Orphaned users can occur due to several reasons, some of which are:

How to Identify Orphaned Users?

The easiest way to identify orphaned users is to run the sp_change_users_login stored procedure. This stored procedure takes three parameters:

• Auto_Fix
• Report
• Update_One

The Auto_Fix parameter is used to automatically fix orphaned users, the Report parameter is used to list all orphaned users, and the Update_One parameter is used to manually fix a specific orphaned user.

Fixing Orphaned Users

Fixing orphaned users involves mapping them to a new login, either an existing login or a new one. There are several methods to fix orphaned users, some of which are:

Method 1: Using sp_change_users_login

The sp_change_users_login stored procedure can be used to fix orphaned users. The Report parameter is used to list all orphaned users, and the Update_One parameter is used to manually fix each orphaned user.

List all orphaned users:

EXEC sp_change_users_login 'Report';

Map a specific orphaned user to a login:

EXEC sp_change_users_login 'Update_One', 'UserName', 'LoginName';

Replace UserName with the name of the orphaned user and LoginName with the name of the new login.

Method 2: Using SQL Server Management Studio

SQL Server Management Studio can also be used to fix orphaned users. The steps are as follows:

1. Connect to the SQL Server instance and expand the Databases folder.
2. Right-click on the database and select Properties.
3. Select the Files tab and note the Logical Name of the database.
4. Run the following query to list all orphaned users:

USE DatabaseName;GOsp_change_users_login 'Report';

5. Right-click on the database and select Tasks > Import Data.
6. Follow the steps in the wizard and import the data into a new database.
7. Run the following query to verify that all users have been mapped to a login:

USE NewDatabaseName;GOsp_change_users_login 'Auto_Fix';

Frequently Asked Questions

What happens if I don’t fix orphaned users?

If you don’t fix orphaned users, they will continue to exist in the database and take up space. They can also cause issues when migrating databases or restoring backups.

Can orphaned users pose a security risk?

No, orphaned users cannot access the database or any data within it. They cannot pose a security risk.

Can I delete orphaned users?

Yes, you can delete orphaned users. However, it is recommended to fix them first, as deleting them may cause issues with the database.

Can I create a new login for an orphaned user?

Yes, you can create a new login for an orphaned user. However, it is recommended to map them to an existing login if possible.

What is the impact of restoring a database with orphaned users?

Restoring a database with orphaned users can cause issues if the login associated with the orphaned user does not exist on the new server. It is recommended to fix orphaned users before restoring a database.

Conclusion

SQL Server orphaned users are database users without any corresponding login in the SQL Server instance. They occur when the login associated with a database user is deleted and the user is not mapped to any other login. Orphaned users can be identified using the sp_change_users_login stored procedure and can be fixed using several methods. It is recommended to fix orphaned users to avoid issues when migrating databases or restoring backups.