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#
# 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 migrate import ForeignKeyConstraint
from sqlalchemy.engine import reflection
from sqlalchemy import MetaData
from sqlalchemy import Table
def upgrade(engine):
meta = MetaData()
meta.bind = engine
def _get_columns(source_table, params):
columns = set()
for column in params:
columns.add(source_table.c[column])
return columns
def _remove_foreign_key_constraints(engine, meta, table_name):
inspector = reflection.Inspector.from_engine(engine)
for fk in inspector.get_foreign_keys(table_name):
source_table = Table(table_name, meta, autoload=True)
target_table = Table(fk['referred_table'], meta, autoload=True)
fkey = ForeignKeyConstraint(
columns=_get_columns(source_table, fk['constrained_columns']),
refcolumns=_get_columns(target_table, fk['referred_columns']),
name=fk['name'])
fkey.drop()
def _drop_table_and_indexes(meta, table_name):
table = Table(table_name, meta, autoload=True)
for index in table.indexes:
index.drop()
table.drop()
table_names = ('watch_data', 'watch_rule')
for table_name in table_names:
_remove_foreign_key_constraints(engine, meta, table_name)
_drop_table_and_indexes(meta, table_name)
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