db_migrate.py

import imp
import os.path

from migrate.versioning import api
from config import SQLALCHEMY_DATABASE_URI, SQLALCHEMY_MIGRATE_REPO
from app import db

migration = os.path.join(os.path.join(SQLALCHEMY_MIGRATE_REPO, 'versions'),
                         '%04d_migration.py' % (api.db_version(SQLALCHEMY_DATABASE_URI, SQLALCHEMY_MIGRATE_REPO) + 1))

tmp_model = imp.new_module('old_model')
old_model = api.create_model(SQLALCHEMY_DATABASE_URI, SQLALCHEMY_MIGRATE_REPO)
exec(old_model, tmp_model.__dict__)
script = api.make_update_script_for_model(SQLALCHEMY_DATABASE_URI, SQLALCHEMY_MIGRATE_REPO, tmp_model.meta, db.metadata)

open(migration, 'wt').write(script)

api.upgrade(SQLALCHEMY_DATABASE_URI, SQLALCHEMY_MIGRATE_REPO)

print('New migration saved as: ' + migration)
print('Current database version: ' + str(api.db_version(SQLALCHEMY_DATABASE_URI, SQLALCHEMY_MIGRATE_REPO)))