Python/Django 中的父/子层次结构/“嵌套集”

发布于 2024-09-07 21:55:04 字数 801 浏览 4 评论 0原文

我使用的是 Django/Python，但伪代码在这里绝对可以接受。

使用一些已经存在的模型，我有 Employee，每个都有一个 Supervisor，这本质上是与另一个 Employee 的外键类型关系。

员工/主管层次结构如下：

任何给定员工都有一名主管。该主管可能有一名或多名“下属”员工，并且也有他/她自己的主管。检索我的“上线”应该返回我的主管、他的主管、她的主管等，直到找到没有主管的员工。

由于这是现有的代码库和项目，因此我想知道实现以下功能的“pythonic”或正确方法：

def get_upline(employee): 
    # Get a flat list of Employee objects that are
    # 'supervisors' to eachother, starting with 
    # the given Employee. 
    pass


def get_downline(employee):
    # Starting with the given Employee, find and 
    # return a flat list of all other Employees 
    # that are "below". 
    pass

我觉得可能有一种稍微简单的方法使用 Django ORM 来做到这一点，但如果没有，我会接受任何建议。

我还没有彻底检查过 Django-MPTT，但是如果我能够保持模型完好无损，并且仅仅获得更多功能，那将是值得的。

原文

I'm using Django/Python, but pseudo-code is definitely acceptable here.

Working with some models that already exist, I have Employees that each have a Supervisor, which is essentially a Foreign Key type relationship to another Employee.

Where the Employee/Supervisor hierarchy is something like this:

Any given Employee has ONE Supervisor. That Supervisor may have one or more Employees "beneath", and has his/her own Supervisor as well. Retrieving my "upline" should return my supervisor, his supervisor, her supervisor, etc., until reaching an employee that has no supervisor.

Without going hog-wild and installing new apps to manage these relationships, as this is an existing codebase and project, I'm wondering the "pythonic" or correct way to implement the following functions:

def get_upline(employee): 
    # Get a flat list of Employee objects that are
    # 'supervisors' to eachother, starting with 
    # the given Employee. 
    pass


def get_downline(employee):
    # Starting with the given Employee, find and 
    # return a flat list of all other Employees 
    # that are "below". 
    pass

I feel like there may be a somewhat simple way to do this with the Django ORM, but if not, I'll take any suggestions.

I haven't thoroughly checked out Django-MPTT, but if I can leave the models in tact, and simply gain more functionality, it would be worth it.

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甜点 2024-09-14 21:55:04

您无需修改模型即可使用 django-mptt；您只需在模型上创建一个 parent 字段，当您注册模型时，django-mptt 会自动为 mptt 创建所有其他属性：mptt.register(MyModel) 。

不过，如果您只需要“上线”层次结构，则不需要嵌套集。更大的性能问题是朝着相反的方向并收集例如。孩子/叶子等，这使得有必要在嵌套集合模型上工作！

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风和你 2024-09-14 21:55:04

关系数据库不适合这种图形查询，因此您唯一的选择就是进行一堆查询。这是一个递归实现：

def get_upline(employee):
    if self.supervisor:
        return [employee] + self.supervisor.get_upline()
    else:
        return [employee]

def get_download(employee):
    l = [employee]
    for minion in self.minion_set.all():
        l.extend(minion.get_download())
    return l

Relational databases are not good for this kind of graph queries, so your only option is to do a bunch of query. Here is a recursive implementation:

def get_upline(employee):
    if self.supervisor:
        return [employee] + self.supervisor.get_upline()
    else:
        return [employee]

def get_download(employee):
    l = [employee]
    for minion in self.minion_set.all():
        l.extend(minion.get_download())
    return l

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