sqlalchemy_alembic_test2.py

from sqlalchemy import create_engine, Column, types
from sqlalchemy.ext.declarative import declarative_base
from sqlalchemy.orm import sessionmaker, scoped_session

Base = declarative_base()

class User(Base):
    __tablename__ = "user"
    id = Column(types.Integer, primary_key=True)
    
engine = create_engine('mysql:///test?unix_socket=/tmp/mysql/socket', echo=True)
session = scoped_session(sessionmaker(bind=engine))
Base.metadata.drop_all(engine)
Base.metadata.create_all(engine)


from alembic.migration import MigrationContext
from alembic.operations import Operations

ctx = MigrationContext.configure(engine)
op = Operations(ctx)

with op.batch_alter_table("user") as batch_op:
    batch_op.add_column(Column('foo', types.Integer))
    batch_op.add_column(Column('bar', types.Integer))