**** CubicPower OpenStack Study ****
def upgrade(migrate_engine):
"""Add provider_geometry column to volumes."""
meta = MetaData()
meta.bind = migrate_engine
volumes = Table('volumes', meta, autoload=True)
provider_geometry = Column('provider_geometry', String(255))
volumes.create_column(provider_geometry)
volumes.update().values(provider_geometry=None).execute()
**** CubicPower OpenStack Study ****
def downgrade(migrate_engine):
"""Remove provider_geometry column from volumes."""
meta = MetaData()
meta.bind = migrate_engine
volumes = Table('volumes', meta, autoload=True)
provider_geometry = Column('provider_geometry', String(255))
volumes.drop_column(provider_geometry)