Python django.db.models 模块，Index() 实例源码

def set_name_with_model(self, model):
        """Sets an unique generated name for the index.

        PartialIndex would like to only override "hash_data = ...", but the entire method must be duplicated for that.
        """
        table_name = model._meta.db_table
        column_names = [model._meta.get_field(field_name).column for field_name, order in self.fields_orders]
        column_names_with_order = [
            (('-%s' if order else '%s') % column_name)
            for column_name, (field_name, order) in zip(column_names, self.fields_orders)
        ]
        # The length of the parts of the name is based on the default max
        # length of 30 characters.
        hash_data = [table_name] + column_names_with_order + [self.suffix] + self.name_hash_extra_data()
        self.name = '%s_%s_%s' % (
            table_name[:11],
            column_names[0][:7],
            '%s_%s' % (self._hash_generator(*hash_data), self.suffix),
        )
        assert len(self.name) <= self.max_name_length, (
            'Index too long for multiple database support. Is self.suffix '
            'longer than 3 characters?'
        )
        self.check_name()