I can't reproduce this with Zope 2.3.3. I have: py_script/alpha: # python script: return context.ex_python.beta() ex_python/beta: # external method calling: def beta(self): return self.db.delta() db/delta: # python script: return 'delta here' All works ok. I didn't use a zsql method here, so maybe that is the problem ? Regards, Florent Guillaume Nuxeo