PERMISSION_SET: SAFE, External_access, and Unsafe
- EXTERNAL_ACCESS enables assemblies to access certain external system resources such as files, networks, environmental variables, and the registry.
- Code executed by an assembly with SAFE permissions cannot access external system resources such as files, the network, environment variables, or the registry.
- UNSAFE enables assemblies unrestricted access to resources, both within and outside an instance of SQL Server. Code running from within an UNSAFE assembly can call unmanaged code.
