流利的nhibernate自动递增非键（Id）属性 [英] fluent nhibernate auto increment non key (Id) property

问题描述

是否可以有一个由数据库管理的类自动增量的整数属性，但不是一个主键（或ID作为NHibernate引用他们）？我无法找到如何做到这一点的例子。任何帮助，将不胜感激。

解决方案

两个选项。
$ b $ ul
<如果数据库是100％负责这个你只需要告诉NHibernate的属性是生成的，不包括它在任何更新/ isnerts。缺点是，NH将需要做一个额外的选择，以保持新鲜的内存价值。

<如果数据库不是负责任的，而且您仅仅是一个数据库，那么您就可以使用这个数据库。想要自动完成这个工作，你可以使用一个拦截器在插入时将该值设置为1，并在更新时将其值加1。

http：//www.nhforge。 org / doc / nh / en / index.html＃objectstate-interceptors （11.1 - 拦截器）

你可以重载OnSave（）来找到属性，设置初始值，然后重写OnFlushDirty（）来查找属性的属性和增量。

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$ b 编辑：

我是一个白痴，没有注意到你说流利的NHibernate。

$ hr

<编辑＃2：

我认为你也可能有兴趣使用这个列作为版本控制？

 <版本名称=Foogenerated =always/> 
  

Is it possible to have an integer property of a class auto increment managed by the database but not be a primary key (or Id as NHibernate refers to them)? I'm having trouble finding examples of how to do this. Any help would be appreciated. Thanks.

解决方案

Two options.

• if the database is 100% responsible for this you just need to tell NHibernate that the property is generated and not to include it in any updates/isnerts. The downside is that NH will need to do an additional select to keep the value fresh in memory.

  < property name="Foo" generated="always" update="false" insert="false" />

• if the database is not responsible and you just want to have this done automatically you can use an interceptor to set the value to 1 on an insert and to increment it by 1 on an update.

http://www.nhforge.org/doc/nh/en/index.html#objectstate-interceptors (11.1 - Interceptors)

You would override OnSave() to find the property and set the initial value and then override OnFlushDirty() to find the property property and increment.

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Edit:

I'm an idiot, didn't notice you said Fluent NHibernate.

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Edit #2:

I think you might also be interested in using this column as a versioning?

< version name="Foo" generated="always" />

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