sqla.py 文件源码

def do_open(self, flags, replace):
        if self.loaded:
            self.flags = flags
            return
        select = sa.select([self.table.c.data],
                           (self.table.c.namespace == self.namespace))
        result = self.bind.execute(select).fetchone()
        if not result:
            self._is_new = True
            self.hash = {}
        else:
            self._is_new = False
            try:
                self.hash = result['data']
            except (IOError, OSError, EOFError, pickle.PickleError,
                    pickle.PickleError):
                log.debug("Couln't load pickle data, creating new storage")
                self.hash = {}
                self._is_new = True
        self.flags = flags
        self.loaded = True