NHibernate：使用数据库中只与FK相关的未提交数据填充列表 [英] NHibernate: populate list with uncommitted data related only by FK in database

问题描述

这是这个问题的阐述和澄清。

假设我有两个表， Foo 和 Bar 。
$ b Bar 的FK为 Foo 。

在应用程序中，表由类表示， Foo 有一个酒吧秒。
Bar 具有 Foo 的id属性，它在数据库中有一个FK。 / p>
$ b 在会话和交易的上下文中， code> IsolationLevel.ReadUncommitted ，我在数据库中添加一个 Foo 的实例，将生成的id赋给 Foo_id Bar 的一个实例的属性，并将其添加到数据库。

Transaction.Commit（）之前， 有可能让NHibernate读出 Foo 与数据库中的 Bar 列表？也就是说，读取的数据未提交？

我有创建了一个演示这个的VS2012项目。它包括一个SSDT项目，用于构建所需的数据库，并且有测试显示我询问的内容。

谢谢

但是，NHibernate通常不会更新已经加载的对象。但是如果你Flush（），接着是Clear（）或者Evict（），然后再读取Foo，它的集合将包含Bar的实例。 （只要你在同一个会话中，提交事务与此无关，除了使用默认设置Commit（）自动调用Flush（）。）

This is an elaboration and clarification of this question.

Suppose I have two tables, Foo and Bar.

Bar has a FK to Foo.

In the application, the tables are represented by classes and Foo has a list of Bars. Bar has a property for the id of the Foo it has a FK to in the database.

In the context of a Session and Transaction with IsolationLevel.ReadUncommitted, I add an instance of Foo to the database, assign the generated id to the Foo_id property of an instance of Bar and also add it to the database.

Now, before calling Transaction.Commit(), is it possible to have NHibernate read out Foo with a list of Bar from the database? That is, read the data uncommitted?

I have created a VS2012 project which demonstrates this. It includes a SSDT project for building the required database and has tests showing what I asking about.

Thank you.

解决方案

In the context of the same transaction you can read back all changes you've made to the database, so yes. The isolation level of the transaction doesn't matter for changes made within that transaction.

However, NHibernate typically won't update an already loaded object. But if you Flush(), followed by either Clear() or Evict() and then read Foo again, its collection will include the instance of Bar. (As long as you are in the same session, committing the transaction is irrelevant to this, except that with default settings Commit() automatically calls Flush().)

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