在 EF 中添加具有现有父级的新记录
我使用实体框架，并在层次结构中包含一组 3 个不同的表。思考公寓单元 ->公寓大楼 ->所有者组织。每个在数据库中都有一个主键和一个其所有者的外键。当我构建 EF 模型时，它为每个模型创建了属性。事实上，保存每个实例的新实例非常容易。例如，我还了解到，要添加新单位，我首先需要添加一个组织，将其添加到新的综合体，然后在保存之前将其添加到新单位。有点工作，但这是有道理的。
我现在感到困惑的是，我有一个新的公寓单元，但它住在一个现有的综合体中。我可以使用适当的属性构建一个新的复杂对象，并将其附加到新单元，但是当我去保存该单元时，框架会在 ApartmentComplex 表中抛出主键冲突，因为它正在尝试添加我将其附加为一个新的综合体，而不是现有的综合体。
对我来说，解决方法似乎是首先检索复合体的一个新实例，而不是构建一个实例 - 实际上，让 EF 代替我构建它 - 但这意味着另一次往返，对我来说似乎有点矫枉过正。有没有更简单的方法来保存我的新公寓单元？
I'm using Entity Framework with a set of 3 different tables, in a hierarchy. Think ApartmentUnit -> ApartmentComplex -> OwnerOrganization. Each has a primary key, and a foreign key to its owner, in the database. When I built the EF model, it created properties for each of those. Indeed, saving new instances of each is pretty easy. I also learned, for example, that to add a new unit, I first need to add an organization, add it to a new complex, then add that to the new unit before saving. A bit of work, but it makes sense.
Where I am confused now is, I have a new apartment unit, but it lives in an existing complex. I can build up a new complex object with the appropriate properties, and attach it to the new unit, but when I go to save the unit, the framework spits up a primary key violation in the apartmentComplex table, as it is trying to add the complex I attached as a NEW complex, not an existing one.
The workaround to me seems to be go and retrieve a new instance of the complex first, instead of building one - in effect, letting the EF build it instead of me - but that would mean another round-trip and seems like overkill to me. Is there a simpler way to save my new Apartment Unit?
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您可以在不访问数据库的情况下创建现有的复合体，但必须在保存之前将其附加到上下文。
You can create the existing complex without going to the DB but you must attach it to the context before you save.