trove/trove/db/sqlalchemy/migrate_repo/versions/030_add_master_slave.py

51 lines
1.7 KiB
Python

# Copyright Tesora, Inc. 2014
#
# 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
#
# http://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.
from sqlalchemy.schema import Column
from sqlalchemy.schema import ForeignKey
from sqlalchemy.schema import MetaData
from trove.db.sqlalchemy.migrate_repo.schema import String
from trove.db.sqlalchemy.migrate_repo.schema import Table
from trove.db.sqlalchemy import utils as db_utils
COLUMN_NAME = 'slave_of_id'
def upgrade(migrate_engine):
meta = MetaData()
meta.bind = migrate_engine
instances = Table('instances', meta, autoload=True)
instances.create_column(
Column(COLUMN_NAME, String(36), ForeignKey('instances.id')),
nullable=True)
def downgrade(migrate_engine):
meta = MetaData()
meta.bind = migrate_engine
instances = Table('instances', meta, autoload=True)
constraint_names = db_utils.get_foreign_key_constraint_names(
engine=migrate_engine,
table='instances',
columns=[COLUMN_NAME],
ref_table='instances',
ref_columns=['id'])
db_utils.drop_foreign_key_constraints(
constraint_names=constraint_names,
columns=[instances.c.slave_of_id],
ref_columns=[instances.c.id])
instances.drop_column(COLUMN_NAME)