[英]SQLAlchemy Combine Multiple Child Classes in one Relationship
I am wondering if somebody can help me out on my SQLAlchemy problem of combining multiple child classes in one relationship.我想知道是否有人可以帮助我解决在一个关系中组合多个子类的 SQLAlchemy 问题。
I am working on a project management app where I have a task breakdown structure as follows:我正在开发一个项目管理应用程序,其中的任务分解结构如下:
Summary Task -> Task -> Subtask -> Located Task摘要任务 -> 任务 -> 子任务 -> 定位任务
Summary Tasks have the ability to reference another summary task forming a hierarchy.摘要任务能够引用另一个形成层次结构的摘要任务。 Meanwhile, tasks does not necessarily belong to a summary task.
同时,任务不一定属于摘要任务。
My current solution is to reference them in separate relationships:我目前的解决方案是在单独的关系中引用它们:
class SummaryTask(Base):
__tablename__ = 'summary_task'
id = Column(Integer, primary_key=True)
schedule_id = Column(ForeignKey('schedule.id'), primary_key=True)
parent_id = Column(Integer)
parent_schedule_id = Column(Integer)
additional_data = Column(Unicode(50))
children = relationship('SummaryTask', backref=backref('parent', remote_side=[id, schedule_id]))
tasks = relationship('Task', backref=backref('parent'))
class Task(Base):
__tablename__ = 'task'
__table_args__ = (ForeignKeyConstraint(['summary_task_id', 'schedule_id'], ['summary_task.id', 'summary_task.schedule_id']))
id = Column(Integer, primary_key=True)
schedule_id = Column(ForeignKey('schedule.id'), primary_key=True)
summary_task_id = Column(Integer)
summary_task = relationship('SumTask')
The code snippet above works for me, but I would like to combine summary tasks (children) and tasks in children, as both are indeed children of summary tasks.上面的代码片段对我有用,但我想将摘要任务(子项)和子项中的任务结合起来,因为两者确实是摘要任务的子项。
class SummaryTask(Base):
...
children = relationship('SummaryTask', 'Task' ...)
My interface will then be as follows from Pydantic:我的界面将如下来自 Pydantic:
class SummaryTaskInterface(BaseModel):
id: int
schedule_id: int
parent_id: Optional[int] = None
parent_schedule_id: Optional[int] = None
additional_data: str
children: List[Union['SummaryTaskInterface', 'TaskInterface']] = []
I hope someone can help my out here.我希望有人能在这里帮助我。
Kind regards亲切的问候
I ended up with this solution.我最终得到了这个解决方案。
class SummaryTask(Base):
__tablename__ = 'summary_task'
id = Column(Integer, primary_key=True)
schedule_id = Column(ForeignKey('schedule.id'), primary_key=True)
parent_id = Column(Integer)
parent_schedule_id = Column(Integer)
additional_data = Column(Unicode(50))
summary_tasks = relationship('SummaryTask', backref=backref('parent', remote_side=[id, schedule_id]))
tasks = relationship('Task', backref=backref('parent'))
@hybrid_property
def children(self):
return self.summary_tasks + self.tasks
With the already suggested interface.使用已经建议的界面。
class SummaryTaskInterface(BaseModel):
id: int
schedule_id: int
parent_id: Optional[int] = None
parent_schedule_id: Optional[int] = None
additional_data: str
children: List[Union['SummaryTaskInterface', 'TaskInterface']] = []
声明:本站的技术帖子网页,遵循CC BY-SA 4.0协议,如果您需要转载,请注明本站网址或者原文地址。任何问题请咨询:yoyou2525@163.com.