old_contents: # Copyright 2012 Managed I.T.
  #
  # Author: Kiall Mac Innes <kiall@managedit.ie>
  #
  # 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 import MetaData, Table, Column
  from moniker.sqlalchemy.types import Inet
  
  meta = MetaData()
  
  
  def upgrade(migrate_engine):
      meta.bind = migrate_engine
  
      servers_table = Table('servers', meta, autoload=True)
  
      ipv4 = Column('ipv4', Inet(), nullable=False, unique=True)
      ipv6 = Column('ipv6', Inet(), default=None, unique=True)
  
      ipv4.create(servers_table, populate_default=True)
      ipv6.create(servers_table, populate_default=True)
  
  
  def downgrade(migrate_engine):
      meta.bind = migrate_engine
  
      servers_table = Table('servers', meta, autoload=True)
  
      ipv4 = Column('ipv4', Inet(), nullable=False, unique=True)
      ipv6 = Column('ipv6', Inet(), default=None, unique=True)
  
      ipv4.drop(servers_table)
      ipv6.drop(servers_table)
  
new_contents: # Copyright 2012 Managed I.T.
  #
  # Author: Kiall Mac Innes <kiall@managedit.ie>
  #
  # 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 import MetaData, Table, Column
  from moniker.sqlalchemy.types import Inet
  
  meta = MetaData()
  
  
  def upgrade(migrate_engine):
      meta.bind = migrate_engine
  
      servers_table = Table('servers', meta, autoload=True)
  
      servers_table.c.ipv4.drop()
      servers_table.c.ipv6.drop()
  
  
  def downgrade(migrate_engine):
      meta.bind = migrate_engine
  
      servers_table = Table('servers', meta, autoload=True)
  
      ipv4 = Column('ipv4', Inet(), nullable=False, unique=True)
      ipv6 = Column('ipv6', Inet(), default=None, unique=True)
  
      ipv4.create(servers_table, populate_default=True)
      ipv6.create(servers_table, populate_default=True)
  
subject: Correct migration #10