Returns whether or not this database table record exists
        in the database.

        :return     <bool>

def isRecord(self, db=None):
        """
        Returns whether or not this database table record exists
        in the database.

        :return     <bool>
        """
        if db is not None:
            same_db = db == self.context().db

        if db is None or same_db:
            col = self.schema().idColumn()
            with ReadLocker(self.__dataLock):
                return (col in self.__loaded) and (self.__values[col.name()][0] is not None)
        else:
            return None