实体框架：检查实体的外键使用的所有关系 [英] Entity Framework: Check all relationships of an entity for foreign key use

问题描述

我有一个实体，我们称之为 CommonEntity 有作为，在许多其他实体的外键的主键。随着应用开发这些链接将继续增长。

I have an entity, let's call it CommonEntity that has a primary key used as a foreign key in many other entities. As the application is developed these links will continue to grow.

我想办法，看看 CommonEntity 可以安全地删除（即它不被任何其他实体）。

I'd like a way to see if CommonEntity can be safely deleted (i.e. it's not used by any other entities).

我知道我能做到

if(!ce.EntityA.Any() && !ce.EntityB.Any() ... && !ce.EntityN.Any())
{
   //Delete
}

但我希望的方式来只是自动检查所有的关系，因为我不喜欢有回来，改变这个code手动每次我们增加一个新的关系的想法。也许有东西在EF4 +，我不知道呢？

but I'm hoping for a way to just check all of the relationships automatically, as I don't love the idea of having to come back and change this code manually every time we add a new relationship. Perhaps there is something in EF4+ that I'm not aware of?

我想这可能是可以使用的交易范围，只是尝试和删除对象，如果失败回滚，但我不知道是否有任何副作用，这种方法。

I thought it might be possible to use a transaction scope to just try and delete the object and roll it back if it fails, but I wasn't sure if there were any adverse side effects with this approach.

有没有更好的方法？

编辑：看起来VS2012采用了EF5尽管该项目是.NET 4中，所以它创造了模型波苏斯即使它从数据库生成

Looks like VS2012 has used EF5 even though the project is .Net 4, so it has created the model with POCOs even though it was generated from a DB.

推荐答案

只是让它失败。如果实体有许多关系，这验证可能是非常沉重的。

Just let it fail. If the entity has many relationships, that verification could be really heavy.

public bool TryDelete(int id)
{
    try
    {
        // Delete
        return true;
    }
    catch (SqlException ex)
    {
        if (ex.Number == 547) return false; // The {...} statement conflicted with the {...} constraint {...}
        throw; // other error
    }
}

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