实体框架拆分表中删除 [英] Entity Framework Split Table Delete

问题描述

我使用EF 4 STE的模型一个附件对象。在附件包含了名称，描述，日期，以及最重要的数据（字节[] ）。为了优化加载，我不想要检索的数据属性，直到它是绝对必要的，即当用户点击下载从客户端。

I'm using EF 4 STE's to model an Attachment object. The Attachment contains a Name, Description, Date, and most importantly Data (byte[]). To optimize loading, I don't want to retrieve the Data property until it's absolutely necessary, i.e. when the user clicks Download from the client.

在努力遵循这种方法，我用的说明表格分裂技术的这里。我拆我的附件表成的附件（名称，描述，日期）和 AttachmentData （数据）。它在我的EF模型1对1的关系。直到我尝试删除的附件无一切的伟大工程，在 AttachmentData （即 attachment.AttachmentData == NULL ）。我得到以下异常：

In an effort to follow this approach, I used the table-splitting technique described here. I split my Attachment table up into Attachment (Name, Description, Date) and AttachmentData (Data). It's a 1-to-1 relationship in my EF model. Everything works great until I try to delete an Attachment without the AttachmentData (i.e. attachment.AttachmentData == null). I get the following exception:

遇到无效数据。一个必需的关系缺失。检查StateEntries确定违反约束的来源。

Invalid data encountered. A required relationship is missing. Examine StateEntries to determine the source of the constraint violation.

我看到了的类似的帖子，但我似乎无法使其与STE的和工作 。ApplyChanges 扩展方法

I saw a similar post, but I can't seem to make it work with STE's and the ApplyChanges extension method.

现在我的数据访问代码很简单：我叫上下文的 ApplyChanges（）然后按的SaveChanges（）。

Right now my data access code is simple: I call context's ApplyChanges() followed by SaveChanges().

我已经尝试了简单删除SQL函数，并映射它这两个实体和实际工作;然而，它打破了刀片。我似乎无法映射所有属性两个实体插入功能。

I've tried a simple delete SQL function and mapped it to both entities and that actually worked; however it broke the insert. I can't seem to map an insert function for all properties to both entities.

这是一些其他的选择，我可以尝试任何想法？附件和AttachmentData之间的关系可以选配？当我让1 0+，我得到一个映射错误说它们的主键可能发生碰撞。

Any ideas on some other options I can try? Can the relationship between Attachment and AttachmentData be optional? When I make it 1 to 0+, I get a mapping error saying that Their primary keys may collide.

开放给任何建议。

谢谢！

推荐答案

解决方案是类似链接的问题，但你必须使用国有贸易企业的特定功能 - ApplyChanges ：

The solution is similar to linked question but you must use specific feature of STEs - ApplyChanges:

context.Attachments.ApplyChanges(att);
if (context.ObjectStateManager.GetObjectStateEntry(att).State == EntityState.Deleted)
{
    var data = new AttachmentData() {Id = att.Id};
    context.AttachmentDataSet.Attach(data);
    context.AttachmentDataSet.DeleteObject(data);
}
context.SaveChanges();

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