Manage authentication and authorization by using T-SQL

Manage authentication and authorization by using T-SQL

As a database administrator working with Microsoft Azure SQL Solutions, you need to ensure secure access to your databases by managing authentication and authorization. In this article, we will explore how to utilize T-SQL to efficiently manage these aspects of database security.

Authentication refers to the process of verifying the identity of a user or client attempting to access the database. On the other hand, authorization involves granting or denying specific privileges or permissions to authenticated users or client applications.

Let’s examine some T-SQL commands and techniques that can be used to manage authentication and authorization in Azure SQL Solutions.

Creating Logins:

To authenticate users, you can create logins that are mapped to Azure Active Directory (Azure AD) accounts or contained database users. This can be accomplished using the CREATE LOGIN statement in T-SQL.

sql
CREATE LOGIN [username]
WITH PASSWORD = ‘password’,
DEFAULT_DATABASE = [database],
DEFAULT_LANGUAGE = [language]

Here, you specify the username and password for the login. Additionally, you can set the default database and language for the login.

Creating Users:

Once a login is created, you need to create a user in the database to provide authorization for accessing specific objects.

sql
CREATE USER [username]
FOR LOGIN [loginname]

Replace `[username]` with the desired name for the user and `[loginname]` with the associated login name. This establishes a link between the login and the user.

Granting Permissions:

To grant permissions to the created user, you can use the GRANT statement. For example, the following command grants the SELECT permission on a table to a specific user.

sql
GRANT SELECT ON [schema].[table]
TO [username]

Replace `[schema]` with the appropriate schema name, `[table]` with the table name, and `[username]` with the user to whom you want to grant the permission.

Revoking Permissions:

If there is a need to revoke permissions previously granted, you can use the REVOKE statement. Here’s an example that revokes the SELECT permission on a table from a user.

sql
REVOKE SELECT ON [schema].[table]
TO [username]

Similar to the GRANT statement, replace `[schema]`, `[table]`, and `[username]` with the respective names.

Managing Roles:

Roles are an excellent way to simplify permission management by providing a central place to assign permissions to multiple users. In Azure SQL Solutions, you have built-in database roles such as db_owner, db_datareader, and db_datawriter.

sql
ALTER ROLE [role_name]
ADD MEMBER [username]

Replace `[role_name]` with the appropriate role, and `[username]` with the user you want to add to that role.

Enforcing Security:

You can enhance security by enforcing strong password policies and requiring Azure AD authentication for logins.

sql
ALTER LOGIN [loginname]
WITH CHECK_POLICY = ON,
CHECK_EXPIRATION = ON,
AUTHENTICATION = [Azure_AD|SQL]

Specify `[Azure_AD]` for Azure AD authentication or `[SQL]` for SQL authentication. Setting `CHECK_POLICY` and `CHECK_EXPIRATION` to ON enforces strong password policies and expiration.

Monitoring Permissions:

Lastly, it is essential to regularly monitor permissions and access rights. You can query system catalog views like sys.database_permissions to analyze permissions granted in the database.

sql
SELECT OBJECT_NAME(major_id) AS [object_name],
USER_NAME(grantee_principal_id) AS [username],
permission_name
FROM sys.database_permissions
WHERE class = 1 — OBJECT_OR_COLUMN

This query retrieves the object names, usernames, and permission names from the sys.database_permissions view, specifically targeting object-level (table, view, etc.) permissions.

By leveraging T-SQL commands and techniques, you can effectively manage authentication and authorization in Azure SQL Solutions, ensuring secure access to your databases. Remember to always follow best practices and regularly review and update your security measures.

In conclusion, this article covered creating logins, users, granting and revoking permissions, managing roles, enforcing security policies, and monitoring permissions using T-SQL. These techniques will assist you in efficiently managing authentication and authorization in Microsoft Azure SQL Solutions.