Fluent NHibernate - 将引用键列设置为 null

发布于 2024-08-29 12:36:46 字数 698 浏览 2 评论 0原文

我有一个约会表和一个约会结果表。在我的 Appointments 表上，我有一个 OutcomeID 字段，其中包含 AppointmentOutcomes 的外键。我的 Fluent NHibernate 映射如下所示；

        Table("Appointments");
        Not.LazyLoad();
        Id(c => c.ID).GeneratedBy.Assigned();
        Map(c => c.Subject);
        Map(c => c.StartTime);
        References(c => c.Outcome, "OutcomeID");


        Table("AppointmentOutcomes");
        Not.LazyLoad();
        Id(c => c.ID).GeneratedBy.Assigned();
        Map(c => c.Description);

使用 NHibernate，如果我删除 AppointmentOutcome，则会抛出异常，因为外键无效。我希望发生的是，删除 AppointmentOutcome 会自动将引用 AppointmentOutcome 的任何约会的 OutcomeID 设置为 NULL。

使用 Fluent NHibernate 可以实现这一点吗？

原文

I have a table of Appointments and a table of AppointmentOutcomes. On my Appointments table I have an OutcomeID field which has a foreign key to AppointmentOutcomes. My Fluent NHibernate mappings look as follows;

        Table("Appointments");
        Not.LazyLoad();
        Id(c => c.ID).GeneratedBy.Assigned();
        Map(c => c.Subject);
        Map(c => c.StartTime);
        References(c => c.Outcome, "OutcomeID");


        Table("AppointmentOutcomes");
        Not.LazyLoad();
        Id(c => c.ID).GeneratedBy.Assigned();
        Map(c => c.Description);

Using NHibernate, if I delete an AppointmentOutcome an exception is thrown because the foreign key is invalid. What I would like to happen is that deleting an AppointmentOutcome would automatically set the OutcomeID of any Appointments that reference the AppointmentOutcome to NULL.

Is this possible using Fluent NHibernate?

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孤芳又自赏 2024-09-05 12:36:46

删除 Outcome 时，需要将 Appointment 对象上的 Outcome 引用设置为 null。

using (var txn = session.BeginTransaction())
{
    myAppointment.Outcome = null;
    session.Delete(outcome);
    txn.Commit();
}

您将关系映射为一对多结果到约会（一个结果可以链接到多个约会）。如果一个结果可以链接到多个约会，那么您需要在删除结果之前取消对所有约会的结果引用（或设置级联删除）。

You need to set the Outcome reference to null on the Appointment object when you delete an Outcome.

using (var txn = session.BeginTransaction())
{
    myAppointment.Outcome = null;
    session.Delete(outcome);
    txn.Commit();
}

You have the relationship mapped as one-to-many Outcome-to-Appointment(one outcome can be linked to multiple appointments). If an Outcome can be linked to multiple appointments then you would need to de-reference Outcome on all of them (or set cascading delete) before deleting the Outcome.

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