Django 管理内联表单 - 将外键查询集限制为一组值

发布于 2024-10-07 04:14:05 字数 1006 浏览 3 评论 0原文

我有一些相互关联的模型需要在单个管理页面上共存。想法是这样的：

戏剧作品有演员，演员有指定的角色。戏剧作品与给定的书面文本（戏剧、改编等）相关，并且书面文本包含该文本的所有角色的列表。添加作品时，每个演员都需要与这些角色之一关联。

数据模型的工作方式如下：

模型：Production、Person、CastMember、Role、WrittenText

关系：Production 和 Person 通过 CastMember 建立 M2M 关系，CastMember 添加一个“角色”字段 - 一个 Role 对象的外键。角色本身有一个指向 WrittenText 对象的外键。

所以，问题是这样的：在 Productions 的管理页面中，我有一个 TabularInline 来添加 CastMembers。表中的 CastMember 条目的“角色”字段应仅限于 Production 引用的 WrittenText 中指定的角色。

我通过覆盖模型表单来解决这个问题：

class CastMemberForm(ModelForm):
    class Meta:
        model = CastMember

    def __init__(self, *args, **kwargs):
        super(CastMemberForm, self).__init__(*args, **kwargs)
        if 'instance' in kwargs:
         self.fields['role'].queryset = Role.objects.filter(source_text=self.instance.production.source_text)

但是，只有当您从下拉列表中选择一个人，保存，然后选择角色时，这才有效 - 否则您只会得到所有角色的列表。取出“if 'instance' in kwargs”会给我一个DoesNotExistError。

如果没有客户端 JS 之类的东西，这是否太复杂了，或者是否有我缺少的更简单的解决方案？

原文

I have some interrelated models that need to co-exist on a single admin page. Here's the idea:

Theater productions have cast members, and cast members have specified roles. A theater production is related to a given written text (play, adaptation, etc.), and the written text holds a list of all the roles for that text. When adding a Production, each cast member needs to be associated with one of those roles.

Here's how the data model is working:

Models: Production, Person, CastMember, Role, WrittenText

Relationships: Production and Person have an M2M relationship through CastMember, which adds a "role" field - a ForeignKey to a Role object. Role itself has a ForeignKey to a WrittenText object.

So, the problem is this: in the admin page for Productions, I have a TabularInline to add CastMembers. The CastMember entries in the table should have their 'role' field limited to only the roles specified in the WrittenText that the Production references.

I made a half-way solution to the problem by overriding the model form:

class CastMemberForm(ModelForm):
    class Meta:
        model = CastMember

    def __init__(self, *args, **kwargs):
        super(CastMemberForm, self).__init__(*args, **kwargs)
        if 'instance' in kwargs:
         self.fields['role'].queryset = Role.objects.filter(source_text=self.instance.production.source_text)

But, this only works if you choose a Person from the drop-down, save, and then choose the role - otherwise you just get a list of all roles. Taking out "if 'instance' in kwargs" gives me a DoesNotExistError.

Is this just way too complex to do without something like client-side JS, or is there a simpler solution that I'm missing?

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