Running yum/apt-get from a virtualenv

[Tiglath Suriol]

Let us say that I install PostgreSQL from an activated virtualenv using yum or apt-get, will PostgrSQL be local or global?  

I understand that virtualenv isolates the Python environment only, so I surmise that it will make no difference installing with yum/apt-get inside or outside the virtualenv.  

But that would not be the case with say Psycopg2 which would be isolated in the virtualenv, because it is a Python module.  Is that right?  

Thanks