# 1/ 初始化环境 
alembic init migrations 

# 2/ 修改alembic.ini参数
# alembic.ini 
sqlalchemy.url = mysql://root:Root1024@localhost/fastapi

# migrations/env.py
import sys 
sys.path = ['', '..'] + sys.path[1:]
from service.models import Base

...
target_metadata = Base.metadata  # 一个app model 
target_metadata = [Base.metadata, Base2.metadata]  # 多个app model

# 3/ 生成迁移脚本
alembic revision --autogenerate -m "init"

# 4/ 应用迁移脚本到数据库
alembic upgrade head