NHibernate on-delete =“级联".与多方面的关系 [英] NHibernate on-delete="cascade" with relationship on many side
问题描述
我有一个这样的对象模型:
I have an object model like that:
-
Folder
-具有名称等的简单结构. -
File
-包含对Folder
的引用的复杂对象.
Folder
- simple structure with name etc.File
- complex object containing reference toFolder
in which it is contained.
文件夹不知道其文件,我也不希望它知道.该关系是多对一,并且应该仅在文件方面知道.
Folder doesn't know its Files and I don't want it to know. The relation is many-to-one and should be known on File's side only.
无论如何,我想依靠数据库的ON DELETE CASCADE功能,以便删除文件夹时,我希望该文件夹中的所有文件都自动删除.我不能使用NHibernate的级联,因为从文件夹到文件没有关系.
Anyway, I would like to rely on my database's ON DELETE CASCADE feature, so that when I remove Folder, I want all Files within that Folder to be deleted automatically. I can't use NHibernate's cascading as there is no relation from Folder to File.
我知道有on-delete="cascade"
选项用于<key>
元素,但是我找不到与我的模型等效的模型-当关系在上定义为时许多方面.
I know that there is on-delete="cascade"
option for <key>
element in case of one-to-many relationship, but I can't find its equivalent for my model - when the relation is defined on many side.
我是在做错什么还是真的需要手动删除已删除文件夹中的所有文件?
Am I doing something wrong or do I really need to go through and delete all the Files within deleted Folder manually?
推荐答案
您可以尝试使用access="noop"
映射一对多面.这样一来,您就无需在类中使用属性,但仍具有映射.
You could try to map the one-to-many side with access="noop"
. That way you don't need a property in your classes but still have the mapping.
在Fluent NHibernate中,应该是这样的:
In Fluent NHibernate that would be someting like this:
HasMany(Reveal.Member<Folder, IEnumerable<File>>("_files"))
.KeyColumn("column_name")
.Access.NoOp()
.Inverse()
.ForeignKeyCascadeOnDelete();
注意:为此,您需要在Folder
类中的类型为IEnumerable<File>
的_files
字段(Fluent NHibernate的限制,只能映射真正存在的字段或属性).但是此字段始终可以为null
,将永远不会使用.
Note: For that you need an _files
field of type IEnumerable<File>
in the Folder
class (limitation of Fluent NHibernate, can only map really existing fields or properties). But this field can always be null
, it will never be used.
这篇关于NHibernate on-delete =“级联".与多方面的关系的文章就介绍到这了,希望我们推荐的答案对大家有所帮助,也希望大家多多支持IT屋!