# Copyright 2019 Google LLC

#

# Licensed under the Apache License, Version 2.0 (the "License");

# you may not use this file except in compliance with the License.

# You may obtain a copy of the License at

#

# https://www.apache.org/licenses/LICENSE-2.0

#

# Unless required by applicable law or agreed to in writing, software

# distributed under the License is distributed on an "AS IS" BASIS,

# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.

# See the License for the specific language governing permissions and

# limitations under the License.

"""Base model for schemas."""

from typing import NoReturn

from spanner_orm import error

from spanner_orm import model

from spanner_orm.admin import api

class InformationSchema(model.Model):

"""Base model for Spanner INFORMATION_SCHEMA tables.

Note: Writes are disallowed and AdminApi is used for reads.

"""

@classmethod

def spanner_api(cls) -> api.SpannerAdminApi:

return api.spanner_admin_api()

@classmethod

def _execute_write(cls, *args) -> NoReturn:

raise error.SpannerError('Writes not allowed for schema tables')