级联删除，同一表，实体框架4代码第一 [英] Cascade Delete, same table, Entity Framework 4 Code First

问题描述

Hi Im目前正在使用.sdf数据库（Server Compact V4.0）和sql express。我试图在同一个表（类别 - 子类别）上设置一个级联删除，但我得到我不能添加到同一个表的关系。

Hi Im currently working with .sdf database (Server Compact Version 4.0) and sql express. I'm trying to setup a cascade delete on a same table (category - sub category) but I get that I cant add relation to the same table.

外键约束和
更新或删除级联规则，
自引用一列相同的
表不允许

A foreign key constraint had and update or a delete cascade rule, and self-references a column in the same table, is not allowed

我可以做些什么？

编辑

我是唯一有这个问题的人？

EDIT
I'm the only one with this problem?

推荐答案

正如您所提出的SQLException一样，这是SQL Server的一般限制，与EF或Code First无关。基本上，SQL Server不允许在内部关系上创建级联操作 - 当级联路径从表A中的列col1到表A中的列col2时。A-> A。

As your SQLException suggested, this is a limitation of SQL Server in general and has nothing to do with EF or Code First. Basically, SQL Server does not allow creating cascade actions on Inner relationships – when the cascade path goes from column col1 in table A to column col2 also in table A. A->A.

事实上，Code First正在尝试使用声明性引用完整性（DRI）来执行级联删除和SQL Server throws。

In fact, Code First was trying to use Declarative Referential Integrity (DRI) to enforce cascade deletes and SQL Server throws.

为此关系执行级联删除的唯一方法是使用触发器。您可以在类别表上写入删除触发器，删除相关行或将所有对应的外键设置为NULL（根据您的要求）。

The only way to enforce cascade deletes for this relationship is to use Triggers. You can write a Delete Trigger on the category table that either deletes the dependent rows or sets all corresponding foreign keys to NULL (based on your requirements).

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