Alembic:如何在模型中迁移自定义类型?

问题描述

我的User模型是

class User(UserMixin, db.Model):
    __tablename__ = 'users'
    # noinspection PyShadowingBuiltins
    uuid = Column('uuid', GUID(), default=uuid.uuid4, primary_key=True,
                  unique=True)
    email = Column('email', String, nullable=False, unique=True)
    _password = Column('password', String, nullable=False)
    created_on = Column('created_on', sa.types.DateTime(timezone=True),
                        default=datetime.utcnow())
    last_login = Column('last_login', sa.types.DateTime(timezone=True),
                        onupdate=datetime.utcnow())

其中GUID是自定义类型，如 sqlalchemy文档(完全相同)

where GUID is a custom type as described in sqlalchemy docs (Exactly same)

现在我跑步

alembic revision --autogenerate -m "Added initial table"

我将upgrade()设置为

def upgrade():
    ### commands auto generated by Alembic - please adjust! ###
    op.create_table('users',
    sa.Column('uuid', sa.GUID(), nullable=False),
    sa.Column('email', sa.String(), nullable=False),
    sa.Column('password', sa.String(), nullable=False),
    sa.Column('created_on', sa.DateTime(timezone=True), nullable=True),
    sa.Column('last_login', sa.DateTime(timezone=True), nullable=True),
    sa.PrimaryKeyConstraint('uuid'),
    sa.UniqueConstraint('email'),
    sa.UniqueConstraint('uuid')
    )
    ### end Alembic commands ###

但是在应用升级-> alembic upgrade head时，我看到

but during applying upgrade -> alembic upgrade head, I see

File "alembic/versions/49cc74d0da9d_added_initial_table.py", line 20, in upgrade
    sa.Column('uuid', sa.GUID(), nullable=False),
AttributeError: 'module' object has no attribute 'GUID'

如何在这里使用GUID/自定义类型使其工作?

How can I make it work with GUID/custom type here?

推荐答案

您可以根据方言将sa.GUID()替换为sa.CHAR(32)或UUID()(在添加导入行from sqlalchemy.dialects.postgresql import UUID之后).

You can replace sa.GUID() with either sa.CHAR(32) or UUID() (after adding the import line from sqlalchemy.dialects.postgresql import UUID) depending on the dialect.

用GUID()替换它(在添加导入行from your.models.custom_types import GUID之后)也可以，但是升级脚本将绑定到您的模型代码，这可能不是一件好事.

Replacing it with GUID() (after adding the import line from your.models.custom_types import GUID) will work also, but then the upgrade script is tied to your model code, which may not be a good thing.

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