LINQ到SQL：调用的SubmitChanges时，执行顺序（）

问题描述：

我有2个相关的数据库表这在简化的形式看起来像这样

I have 2 related database tables which in simplified form look like this

Product(
  product_id,
  name
)

ProductSpecs(
  spec_id,
  product_id,
  name,
  value
)

外键是通过PRODUCT_ID字段设置和ProductSpecs表对（产品编号，名称）对唯一的约束。

Foreign key is set via product_id field and ProductSpecs table has a unique constraint on (product_id, name) pair.

现在的我，当用户编辑产品规格和保存数据，我删除旧的规范和插入所有的新的ASP.NET MVC应用程序。

Now in my ASP.NET MVC application when user edits product specs and saves the data I delete old specs and insert all as new ones.

我做到这一点，首先调用DataContext.DeleteAllOnSubmit（），并提供电流（旧）ProductSpecs作为参数，然后我添加新的功能到Product.ProductSpecs集合。

I do this by first calling DataContext.DeleteAllOnSubmit() and providing current (old) ProductSpecs as a parameter, and then I add new specs to the Product.ProductSpecs collection.

然后我打电话DataContext.SubmitChanges（），并得到一个错误，我的唯一约束被侵犯。

Then I call DataContext.SubmitChanges() and get an error that my unique constraint was violated.

通过查看由DataContenxt.GetChangeText返回的SQL语句（）我可以看到嵌件的DELETE之前执行（尽管我叫DeleteAllOnSubmit（）添加前）。

By looking at the SQL statements returned by DataContenxt.GetChangeText() I can see that INSERTs are executed before DELETEs (even though I called DeleteAllOnSubmit() before Add).

什么是这种现象的原因以及如何解决或解决方法呢？

What is the reason of this behavior and how to fix or workaround it?

感谢。

答

是的，出于某种原因，LINQ to SQL的执行所有删除的最后一件事。而且也没有办法改变这一点。

Yes, for some reason, Linq to SQL perform all deletes as the last thing. And there is no way to change that.

或许有。我没有看过成codeGEN的DataContext，看看我们是否可以覆盖一些东西在那里。

Or maybe there is. I haven't looked into the codegen DataContext to see if we can override something there.

您可以调用的SubmitChanges（），你要尽可能多的时间。我的解决方法，当我需要删除的第一件事情，是记住我删除，调用的SubmitChanges（），然后执行插入和更新，并再次呼吁的SubmitChanges。

You can call SubmitChanges() as many times you want. My workaround when I need to delete as the first thing, is mark my deletions, call SubmitChanges(), then perform inserts and updates, and call SubmitChanges once again.

你可以用一切一个TransactionScope内：

You can wrap everything inside of a TransactionScope:

    var deletables =
        from toDelete in db.NamedValues
        where toDelete.Name == knownValue.Name
        select toDelete;

    using (var scope = new TransactionScope())
    {
        db.NamedValues.DeleteAllOnSubmit(deletables);
        db.SubmitChanges();

        db.NamedValues.InsertOnSubmit(knownValue);
        db.SubmitChanges();

        scope.Complete();
    }

LINQ到SQL：调用的SubmitChanges时，执行顺序（）

相关推荐