OpenStack Study: 034_add_virtual_size.py

**** CubicPower OpenStack Study ****

def upgrade(migrate_engine):

    meta = sqlalchemy.MetaData()

    meta.bind = migrate_engine

    images = sqlalchemy.Table('images', meta, autoload=True)

    virtual_size = sqlalchemy.Column('virtual_size',

                                     sqlalchemy.BigInteger)

    images.create_column(virtual_size)

**** CubicPower OpenStack Study ****

def downgrade(migrate_engine):

    meta = sqlalchemy.MetaData()

    meta.bind = migrate_engine

    images = sqlalchemy.Table('images', meta, autoload=True)

    images.columns['virtual_size'].drop()