Fixed server roles and fixed database roles are assigned specific permissions by SQL Server. The permissions of the fixed roles cannot be changed. Fixed server and fixed database roles are provided for convenience and backward compatibility. Beginning with SQL Server 2005, a more granular permission system is available. Microsoft recommends that you assign the more specific permissions whenever possible.
The following illustration shows the permissions held by the fixed server roles.
Important The ability to grant access to the Database Engine and to configure user permissions allows the security admin to assign most server permissions. The securityadmin role should be treated as equivalent to the sysadmin role.
The following illustration shows the permissions held by the fixed database roles.
Maheshkumar S Tiwari edited Original. Comment: Added Tag