如何与 Fluent NHibernate 映射可选的一对一关系？
我有两个实体，一个称为“站点”，另一个称为“分配”。站点可能有也可能没有关联的分配。一项分配仅与一个站点相关联。就C#而言，Site有一个Assignment类型的属性，它可以保存空引用。
我在数据库中有两个同名的表。分配表的 PK 也是其返回到站点表的 FK（而不是具有指向分配的可空 FK 的站点）。 SQL（为简洁起见省略了字段）如下所示，
CREATE TABLE Site(
SiteId INT NOT NULL CONSTRAINT PK_Site PRIMARY KEY)
CREATE TABLE Assignment(
AssignmentId INT NOT NULL CONSTRAINT PK_Assignment PRIMARY KEY,
CONSTRAINT FK_Assignment_Site FOREIGN KEY (AssignmentId) REFERENCES Site (SiteId))
我正在使用 Fluent NHibernate 的自动持久性模型，我认为我必须添加一个覆盖才能使其正常工作。我的问题是，如何映射这种关系？我的模式对于这种情况是否正确？如果需要，我可以更改架构。
I've got two entities, one called Site and the other called Assignment. A Site may or may not have an associated Assignment. An Assignment is only ever associated with one Site. In terms of C#, Site has a property of type Assignment which could hold a null reference.
I have got two tables by the same names in the database. The Assignment table's PK is also its FK back to the Site table (rather than Site having a nullable FK pointing to Assignment). The SQL (with fields omitted for brevity) is as follows
CREATE TABLE Site(
SiteId INT NOT NULL CONSTRAINT PK_Site PRIMARY KEY)
CREATE TABLE Assignment(
AssignmentId INT NOT NULL CONSTRAINT PK_Assignment PRIMARY KEY,
CONSTRAINT FK_Assignment_Site FOREIGN KEY (AssignmentId) REFERENCES Site (SiteId))
I'm using Fluent NHibernate's auto persistence model, which I think I will have to add an override to in order to get this to work. My question is, how do I map this relationship? Is my schema even correct for this scenario? I can change the schema if needs be.
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您需要阅读这些：
这是不可能进行一对一的延迟加载，除非它们不可为空，或者将它们映射为其中包含一项的多对一
You need to read these:
it's not possible to have one-to-ones lazy loaded unless they are not-nullable, or you map them as a many-to-one with one item in it