Alembic:如何在模型中迁移自定义类型？

Question

我的User模特是

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sqlalchemy docs中描述的自定义类型(完全相同)

现在我跑的时候

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

我得到了我upgrade()的

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 ###

但在应用升级期间 - > alembic upgrade head,我明白了

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GUID在此处使用/自定义类型？

Answer 1

您可以根据方言替换sa.GUID()为sa.CHAR(32)或者UUID()(在添加导入行之后from sqlalchemy.dialects.postgresql import UUID).

用GUID()(在添加导入行之后from your.models.custom_types import GUID)替换它也可以,但是升级脚本与你的模型代码绑定,这可能不是一件好事.