**** CubicPower OpenStack Study ****
def upgrade(migrate_engine):
meta = MetaData()
meta.bind = migrate_engine
nodes = Table('bm_nodes', meta, autoload=True)
nodes.drop_column('prov_vlan_id')
nodes.drop_column('registration_status')
**** CubicPower OpenStack Study ****
def downgrade(migrate_engine):
meta = MetaData()
meta.bind = migrate_engine
nodes = Table('bm_nodes', meta, autoload=True)
nodes.create_column(Column('prov_vlan_id', Integer))
nodes.create_column(Column('registration_status', String(length=16)))