Extending MDX using External Functions - Professional SQL Server Analysis Services 2005 with MDX - page 499

ing reflection, Analysis Services Tools is able to retrieve the functions
available in the assembly. During runtime this code is compiled into
machine language and then executed by the .NET framework.
Figure 10-4
5. Select a permission set option for the assemblies you are adding.
Analysis Services leverages permission sets from the .NET frame-
work to provide fine-grain security on the assemblies being added to
Analysis Services. You can select three different permission set op-
tions:
1. Safe: The Safe permission set forces the assembly to only
perform computation operations. Whenever a stored pro-
cedure marked with the Safe permission set tries to access
external resources, the .NET framework restricts the permis-
sion and throws an error.
2. External Access: The External Access permission set is in-
tended to allow managed code to access external resources
from the server, without compromising the reliability of the
server. You can use this if you as the DBA trust the pro-
grammer's ability to write good code and if there is a need to
access external resources such as data from an outside file.
3. Unrestricted: If an assembly has been marked with the Un-
restricted permission set, it can perform any operations on
the server or on any external resources. The Unrestricted