What are the differences between using roles and groups to manage T-SQL permissions?

1 What are roles?

Roles are collections of permissions that can be assigned to users or other roles. Roles can simplify the administration of permissions by allowing you to grant or revoke multiple permissions at once. Roles can also inherit permissions from other roles, creating a hierarchy of access levels. T-SQL supports two types of roles: fixed roles and user-defined roles. Fixed roles are predefined by SQL Server and have specific permissions for database administration, security, and maintenance. User-defined roles are created by users and can have any combination of permissions that the user can grant.

2 What are groups?

Groups are collections of users that can be treated as a single entity for permission purposes. Groups can be created at the Windows level or at the SQL Server level. Windows groups are defined by the operating system and can contain Windows users or other Windows groups. SQL Server groups are defined by SQL Server and can contain SQL Server users or other SQL Server groups. Groups can be members of roles, but roles cannot be members of groups. Groups can also have permissions directly assigned to them, but this is not recommended as it can create confusion and inconsistency.

3 How to create roles?

To create a user-defined role, you can use the CREATE ROLE statement in T-SQL. You need to specify the name of the role and optionally the authorization, which is the principal that owns the role. For example, to create a role named SalesReport that is owned by the user John, you can use this statement: CREATE ROLE SalesReport AUTHORIZATION John; To grant permissions to a role, you can use the GRANT statement in T-SQL. You need to specify the permission, the object, and the role. For example, to grant the SalesReport role the permission to execute the GetSales stored procedure, you can use this statement: GRANT EXECUTE ON GetSales TO SalesReport; To add users or other roles to a role, you can use the ALTER ROLE statement in T-SQL. You need to specify the role and the member. For example, to add the user Mary and the role Analyst to the SalesReport role, you can use these statements: ALTER ROLE SalesReport ADD MEMBER Mary; ALTER ROLE SalesReport ADD MEMBER Analyst;

4 How to create groups?

To create a Windows group, you need to use the Windows tools and settings, such as Active Directory or Computer Management. You need to specify the name of the group and the members, which can be Windows users or other Windows groups. To create a SQL Server group, you need to use the CREATE LOGIN statement in T-SQL. You need to specify the name of the group and the type, which must be WINDOWS GROUP. For example, to create a SQL Server group named SalesTeam that corresponds to a Windows group, you can use this statement: CREATE LOGIN SalesTeam FROM WINDOWS WITH DEFAULT_DATABASE = Sales; To add groups to roles, you can use the same ALTER ROLE statement as for users or roles. For example, to add the SalesTeam group to the SalesReport role, you can use this statement: ALTER ROLE SalesReport ADD MEMBER SalesTeam;

5 When to use roles and groups?

Roles and groups are both useful tools for managing permissions, but they have different purposes and advantages. Roles are more flexible and granular, as they can have any permissions and can be nested within other roles. Roles are also more portable, as they are independent of the authentication method and can be easily transferred between databases. Groups are more convenient and efficient, as they can reduce the number of principals and permissions to manage. Groups are also more secure, as they rely on the Windows authentication and can enforce the principle of least privilege. Generally, you should use roles to define the permissions for different tasks or functions, and use groups to organize the users or roles that perform those tasks or functions.

6 Here’s what else to consider

This is a space to share examples, stories, or insights that don’t fit into any of the previous sections. What else would you like to add?