NHibernate的/ ActiveRecord的：如何设置没有得到整个物体的外键？ [英] NHibernate / ActiveRecord: How to set foreign key without getting entire object?

问题描述

比方说，我有以下ActiveRecord类：

Let's say I've got the following ActiveRecord class:

[ActiveRecord]
public class Account
{
    ...

    [BelongsTo("CustomerId")]
    public Customer Customer { get; set; }
}

目前，要我必须从数据库中获取整个客户对象，并将其分配给帐户设置在客户字段的值：

Currently, to set the value of the CustomerId field I have to get the entire Customer object from the database and assign it to the Account:

Customer customer = Customer.FindById(1);
account.Customer = customer;

这是效率不高。我宁愿直接设置客户id字段的值，而无需往返数据库，如：

This isn't very efficient. I'd rather set the value of CustomerId field directly without round-tripping the database, e.g.

account.CustomerId = 1;

什么是做了正确的方法是什么？

What's the correct way to do this?

推荐答案

您可以实现MK8k在ActiveRecord的解决方案。它是这样的：

You can implement MK8k's solution in ActiveRecord. It would look like this:

using (new SessionScope()) {
    var ghostCustomer = Customer.Find(customerId);

    var account = Account.TryFind(accountId);
    account.Customer = ghostCustomer;
}

两个要点：

的Customer.Find必须在SessionScope。 Find方法检查，并会完全加载如果SessionScope没有定义你的对象。

The Customer.Find must be in a SessionScope. The Find method checks and will fully load your object if a SessionScope is not defined.

Customer类必须定义为懒惰。 NHibernate的将不使用代理非延迟的类。

The Customer class must be defined as lazy. NHibernate will not use a proxy for a non-lazy class.

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