flask迁移和更改列类型

Question

我正在尝试学习一些Flask，并且正在使用Flask-Migrate 1.6.0

所以我做了一个看起来像这样的模型

class Download(db.Model):

    __tablename__ = "downloads"

    id = db.Column(db.Integer, autoincrement=True, primary_key=True)
    filename = db.Column(db.String, nullable=False)
    size = db.Column(db.Integer, nullable=False)
    location = db.Column(db.String, nullable=False)
    season = db.Column(db.Integer, nullable=False)
    download_timestamp = db.Column(db.DateTime, nullable=False)

    show_id = db.Column(db.Integer, ForeignKey("shows.id"))

    def __init__(self,filename,size,location,timestamp,season):
        self.filename = filename
        self.size = size
        self.location = location
        self.download_timestamp = timestamp
        self.season = season

    def __repr__(self):
        return '<File {}'.format(self.filename)

然后我将其更改为完全相同的东西，除了这一行：

size = db.Column(db.BigInteger, nullable=False)

当我运行我的

manager.py db migrate

命令，它不会检测列类型的更改。我已经阅读了它，我知道当我更改env.py并添加compare_type = True变量时，它应该将其选中。但是我这样做无济于事，该方法现在看起来像这样

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.

    """

    # this callback is used to prevent an auto-migration from being generated
    # when there are no changes to the schema
    # reference: http://alembic.readthedocs.org/en/latest/cookbook.html
    def process_revision_directives(context, revision, directives):
        if getattr(config.cmd_opts, 'autogenerate', False):
            script = directives[0]
            if script.upgrade_ops.is_empty():
                directives[:] = []
                logger.info('No changes in schema detected.')

    engine = engine_from_config(config.get_section(config.config_ini_section),
                                prefix='sqlalchemy.',
                                poolclass=pool.NullPool)

    connection = engine.connect()
    context.configure(connection=connection,
                      target_metadata=target_metadata,
                      compare_type=True,
                      process_revision_directives=process_revision_directives,
                      **current_app.extensions['migrate'].configure_args)

    try:
        with context.begin_transaction():
            context.run_migrations()
    finally:
        connection.close()

好的，所以我的问题是：

更改env.py文件时我做错什么了吗？

如果没有，但仍然无法解决，该如何准确手动进行下一个迁移修订？因为我的迁移文件夹中的修订版的名称如下所示，其内容如下

# revision identifiers, used by Alembic.
revision = '7e9f264b0f'
down_revision = '2e59d536f50'

我想我可以只复制一个，组成一个名字..但是，被flask吸收的下一个可以迁移吗？所以，是的..避免过多恶意攻击的正确方法是什么？

Answer 1

只需在Migrate构造函数中添加compare_type = True

from flask_migrate import Migrate
migrate = Migrate(compare_type=True)

app = Flask(__name__)
migrate.init_app(app)