def deferrable_sql(self):
        return ''
Returns True if a file referened by the given name already exists in the
dataset/ETHPy150Open AppScale/appscale/AppServer/lib/django-1.2/django/db/backends/__init__.py/BaseDatabaseOperations.deferrable_sql--crossover with--dataset/ETHPy150Open dcramer/django-compositepks/django/core/files/storage.py/Storage.exists