migrate之alembic无法生成表

第一次删除了migrate文件夹

执行upgrade 发现没有生成表，然后versions文件夹中都是空的。

alembic init --template generic migrate # 使用generic目标，创建一个migrate文件夹，并初始化。
alembic revision --autogenerate -m "initdb"
alembic revision --autogenerate -m "added user table"
alembic  upgrade head #或者跟版本号

修改env.py文件如下。

from logging.config import fileConfig

from sqlalchemy import engine_from_config
from sqlalchemy import pool

from alembic import context
from db import Base
# this is the Alembic Config object, which provides
# access to the values within the .ini file in use.
config = context.config

# Interpret the config file for Python logging.
# This line sets up loggers basically.
if config.config_file_name is not None:
    fileConfig(config.config_file_name)

# add your model's MetaData object here
# for 'autogenerate' support
# from myapp import mymodel
# target_metadata = mymodel.Base.metadata
from model import * #重点1
target_metadata = Base.metadata #重点二

# other values from the config, defined by the needs of env.py,
# can be acquired:
# my_important_option = config.get_main_option("my_important_option")
# ... etc.


def run_migrations_offline():
    """Run migrations in 'offline' mode.

    This configures the context with just a URL
    and not an Engine, though an Engine is acceptable
    here as well.  By skipping the Engine creation
    we don't even need a DBAPI to be available.

    Calls to context.execute() here emit the given string to the
    script output.

    """
    url = config.get_main_option("sqlalchemy.url")
    context.configure(
        url=url,
        target_metadata=target_metadata,
        literal_binds=True,
        dialect_opts={"paramstyle": "named"},
    )

    with context.begin_transaction():
        context.run_migrations()


def run_migrations_online():
    """Run migrations in 'online' mode.

    In this scenario we need to create an Engine
    and associate a connection with the context.

    """
    connectable = engine_from_config(
        config.get_section(config.config_ini_section),
        prefix="sqlalchemy.",
        poolclass=pool.NullPool,
    )

    with connectable.connect() as connection:
        context.configure(
            connection=connection, target_metadata=target_metadata
        )

        with context.begin_transaction():
            context.run_migrations()


if context.is_offline_mode():
    run_migrations_offline()
else:
    run_migrations_online()

可以看下我们的目录

|-model
---- __init__.py
---- userModel.py

userModel.py 如下：

from db import Base
from sqlalchemy import Column, Integer, String,Boolean, ForeignKey
class UserModel(Base):
    __tablename__ = 'user'
    id = Column(Integer,primary_key=True)
    username = Column(String(255),nullable=False,unique=True)
    passwd = Column(String(255),nullable=False)
    sex = Column(Boolean,nullable=False)
    post = Column(String(100),nullable=False)
    department = Column(String(200),nullable=False)
    isActive = Column(Boolean,nullable=False)
    roleId = Column(Integer,ForeignKey("role.id"),default=0)

    def __init__(self,username,passwd,sex) -> None:
        self.username = username
        self.passwd = passwd
        self.sex = sex

    def __repr__(self) -> str:
        return "<User {}>".format(self.username)

init.py如下：

from .userModel import UserModel
from .roleModel import RoleModel

db.py如下：

from sqlalchemy import create_engine
from sqlalchemy.orm import scoped_session, sessionmaker
from sqlalchemy.ext.declarative import declarative_base
from config import Config


engine = create_engine(Config.SQLALCHEMY_DATABASE_URI,echo=True)
db_session = scoped_session(sessionmaker(autocommit=False,
                                         autoflush=False,
                                         bind=engine))

Base = declarative_base()
Base.query = db_session.query_property()                                         
def init_db(app):
    # 在这里导入定义模型所需要的所有模块，这样它们就会正确的注册在
    # 元数据上。否则你就必须在调用 init_db() 之前导入它们。
    # import yourapplication.models
    from model import UserModel
    Base.metadata.create_all(bind=engine)