python-3.x - Python PonyORM 一对一映射

Question

我正在尝试使用 Pony ORM 创建一对一映射。

class ApplierIngress(ApplierObjectMapper.db.Entity):
    correlation_id = orm.PrimaryKey(str)
    ticket_number  = orm.Required(str)
    username       = orm.Required(str)
    status         = orm.Required(str)
    request_date   = orm.Required(datetime)

class ApplierResult(ApplierObjectMapper.db.Entity):
    correlation_id = orm.Required(ApplierIngress)
    result         = orm.Required(orm.LongStr)
    request_date   = orm.Required(datetime)

生成映射时抛出错误

pony.orm.core.ERDiagramError:找不到 ApplierResult.correlation_id 的反向属性

我希望 ApplierResult 表中的 correlation_id 是引用 ApplierIngress 表中的 correlation_id 的外键

请告诉我我做错了什么？

Answer 1

如错误所述，您需要指定反向属性。实体不仅仅是表。

class ApplierIngress(ApplierObjectMapper.db.Entity):
    correlation_id = orm.PrimaryKey(str)
    ticket_number  = orm.Required(str)
    username       = orm.Required(str)
    status         = orm.Required(str)
    request_date   = orm.Required(datetime)
    result_id      = orm.Optional('ApplierResult') # this attribute should be added       

class ApplierResult(ApplierObjectMapper.db.Entity):
    correlation_id = orm.Required(ApplierIngress)
    result         = orm.Required(orm.LongStr)
    request_date   = orm.Required(datetime)

因为这个类还没有声明你应该把它作为字符串或者 lambda 来使用

result_id = orm.Optional('ApplierResult')

result_id = orm.Optional(lambda: ApplierResult)

参见 here