为什么更新外键后引用约束不一致？

Question

抱歉这个模糊的标题,很难用一行描述:

我有2个实体User和UserAddress,其中用户有2个外键DefaultInvoiceAddressId和DefaultDeliveryAddressId和UserAddress有一个UserId外键.

用户对象具有默认地址(DefaultInvoiceAddress和DefaultDeliveryAddress)的导航属性以及用于其所有地址的导航属性:AllAddresses.

映射等工作,创建和更新用户和地址也有效.

但是不起作用的是将用户的现有地址设置为例如DefaultInvoiceAddress.在SQL术语中,我想要发生的是UPDATE USER SET DefaultInvoiceAddressId = 5 WHERE Id = 3.

我试过以下方式:

private void MarkAs(User user, UserAddress address, User.AddressType type) {
        if (context.Entry(user).State == EntityState.Detached)
            context.Users.Attach(user);

        // guess I don't really need this:
        if (context.Entry(address).State == EntityState.Detached)
            context.UserAddresses.Attach(address);

        if (type.HasFlag(User.AddressType.DefaultInvoice)) {
            user.DefaultInvoiceAddressId = address.Id;
            user.DefaultInvoiceAddress = null;
            context.Entry(user).Property(u => u.DefaultInvoiceAddressId).IsModified = true;
        }

        if (type.HasFlag(User.AddressType.DefaultDelivery)) {
            user.DefaultDeliveryAddressId = address.Id;
            user.DefaultDeliveryAddress = null;
            context.Entry(user).Property(u => u.DefaultDeliveryAddressId).IsModified = true;
        }
    }

在创建新的UserAddresses以及更新地址时都会调用此方法.创建方案按预期工作,但在更新的情况下,我收到以下错误:

The changes to the database were committed successfully, 
but an error occurred while updating the object context. 
The ObjectContext might be in an inconsistent state. 
Inner exception message: A referential integrity constraint violation occurred: 
The property values that define the referential constraints are not consistent between principal and dependent objects in the relationship.

我用一个User对象调用该方法,我从数据库中检索它和它包含的DefaultDeliveryAddress,我通过eager loading加载它.

var user = mainDb.User.Get(UnitTestData.Users.Martin.Id, User.Include.DefaultAddresses);
var existingAddress = user.DefaultDeliveryAddress;
mainDb.User.Addresses.SetAs(user, existingAddress, User.AddressType.DefaultInvoice))
// the SetAs method verfies input parameters, calls MarkAs and then SaveChanges

简而言之,我只想让用户的DefaultDeliveryAddress也是他的DefaultInvoiceAddress,这可以通过上面的SQL Update命令轻松完成,但我遗漏了我的EF代码.我已经检查过了:

• 仅设置了Id,导航属性(DefaultInvoiceAddress)被重置为null
• UserAddress.UserId = User.Id(显然因为它已经分配给用户)
• 用户对象将变为Modified(使用调试器检查),因为其中一个属性被标记为已修改
• 我也尝试清除两个默认地址导航属性,但这也没有帮助

我怀疑这个问题是由于User实体有2个UserAddress引用,并且两个外键都设置为引用相同的地址 - 我怎样才能让EF使用它？

更新:

以下是User实体的映射:

// from UserMap.cs:
...
        Property(t => t.DefaultInvoiceAddressId).HasColumnName("DefaultInvoiceAddressId");
        Property(t => t.DefaultDeliveryAddressId).HasColumnName("DefaultDeliveryAddressId");

        // Relationships
        HasOptional(t => t.DefaultInvoiceAddress)
            .WithMany()
            .HasForeignKey(t => t.DefaultInvoiceAddressId);

        HasOptional(t => t.DefaultDeliveryAddress)
            .WithMany()
            .HasForeignKey(t => t.DefaultDeliveryAddressId);

        HasMany(t => t.AllAddresses)
            .WithRequired()
            .HasForeignKey(t => t.UserId)
            .WillCascadeOnDelete();

UserAddress没有返回用户的导航属性; 它只有contanis HasMaxLength和HasColumnName设置(我排除它们以保持问题有点可读).

更新2

这是Intellitrace执行的命令:

The command text "update [TestSchema].[User]
set [DefaultInvoiceAddressId] = @0
where ([Id] = @1)
" was executed on connection "Server=(localdb)\..."

对我来说很好看; 似乎只有EF状态管理器才会被键映射混淆.

Answer 1

找出问题:显然,将导航属性设置为null会产生很大的不同,因为EF可能会将其解释为预期的更改/更新(至少这是我怀疑的).

以下版本的MarkAs方法有效:

private void MarkAs(User user, UserAddress address, User.AddressType type) {
        if (context.Entry(user).State == EntityState.Detached) {
            // clear navigation properties before attaching the entity
            user.DefaultInvoiceAddress = null;
            user.DefaultDeliveryAddress = null;
            context.Users.Attach(user);
        }
        // address doesn't have to be attached

        if (type.HasFlag(User.AddressType.DefaultInvoice)) {
            // previously I tried to clear the navigation property here
            user.DefaultInvoiceAddressId = address.Id;
            context.Entry(user).Property(u => u.DefaultInvoiceAddressId).IsModified = true;
        }

        if (type.HasFlag(User.AddressType.DefaultDelivery)) {
            user.DefaultDeliveryAddressId = address.Id;
            context.Entry(user).Property(u => u.DefaultDeliveryAddressId).IsModified = true;
        }
    }

总结我对未来读者的发现:

• 如果您打算通过外键属性更新实体,请清除导航属性.EF不需要他们来计算更新语句.
• 在将实体附加到上下文之前清除导航属性,否则EF可能会将其解释为更改(在我的情况下,外键可以为空,如果不是这种情况,则EF可能足够聪明以忽略导航属性更改).

我不会马上接受我自己的回答,让其他(更有资格的)读者有机会回答; 如果在接下来的两天内没有发布答案,我会接受这个答案.