EF6无法为表拆分/共享主键+基类建立模型

Question

问题

根据我之前的问题，我正试图使用表拆分来共享一个大约7个实体的大表(200多个字段)。

EF6不仅需要从主模型到子模型的导航属性，还需要所有子模型之间的导航属性(这很糟糕)。

手动解决方案

这可以手动完成：

public class Franchise
{
[Key]
public int Id { get; set; }
public virtual FranchiseEntity Entity { get; set; }
public virtual FranchiseMiscellaneous Miscellaneous { get; set; }
}
[Table("Franchise")]
public class FranchiseEntity
{
[Key]
public int Id { get; set; }
public virtual FranchiseEntity Entity { get; set; } // Ignored, but relevant when inheritance involved, below...
public virtual FranchiseMiscellaneous Miscellaneous { get; set; }
}
[Table("Franchise")]
public class FranchiseMiscellaneous
{
[Key]
public int Id { get; set; }
public virtual FranchiseEntity Entity { get; set;
public virtual FranchiseMiscellaneous Miscellaneous { get; set; }  // Ignored, but relevant when inheritance involved, below...
}

具有流畅的映射：

public class FranchiseMapping : EntityTypeConfiguration<Franchise>
{
public FranchiseMapping()
{
HasRequired(x => x.Entity).WithRequiredPrincipal();
HasRequired(x => x.Miscellaneous).WithRequiredPrincipal();
}
}
public class FranchiseEntityMapping : EntityTypeConfiguration<FranchiseEntity>
{
public FranchiseEntityMapping()
{
Ignore(x => x.Entity);
HasRequired(x => x.Miscellaneous).WithRequiredPrincipal(x => x.Entity);
}
}
public class FranchiseMiscellaneousMapping : EntityTypeConfiguration<FranchiseMiscellaneous>
{
public FranchiseMiscellaneousMapping()
{
Ignore(x => x.Miscellaneous);
}
}

这是有效的。但它不会，这将不会很好地扩展到7个以上的模型。

尝试改进#1

我想通过继承+DRY原则进行改进：

public abstract class SharedFranchiseIdBase
{
[Key]
public int Id { get; set; }
public virtual FranchiseEntity Entity { get; set; }
public virtual FranchiseMiscellaneous Miscellaneous { get; set; }
}
public class Franchise : SharedFranchiseIdBase { ... }
public class FranchiseEntity : SharedFranchiseIdBase { ... }
public class FranchiseMiscellaneous : SharedFranchiseIdBase { ... }
// Maybe generalize the mapping code too...

但第一次请求"序列包含多个匹配元素"时失败：

System.Reflection.TargetInvocationException: Exception has been thrown by the target of an invocation. ---> System.InvalidOperationException: Sequence contains more than one matching element
Result StackTrace:  
at System.Linq.Enumerable.Single[TSource](IEnumerable`1 source, Func`2 predicate)
at System.Data.Entity.ModelConfiguration.Configuration.Properties.Navigation.NavigationPropertyConfiguration.ConfigureDependentBehavior(AssociationType associationType, EdmModel model, EntityTypeConfiguration entityTypeConfiguration)
at System.Data.Entity.ModelConfiguration.Configuration.Properties.Navigation.NavigationPropertyConfiguration.Configure(NavigationProperty navigationProperty, EdmModel model, EntityTypeConfiguration entityTypeConfiguration)
at System.Data.Entity.ModelConfiguration.Configuration.Types.EntityTypeConfiguration.ConfigureAssociations(EntityType entityType, EdmModel model)
at System.Data.Entity.ModelConfiguration.Configuration.Types.EntityTypeConfiguration.Configure(EntityType entityType, EdmModel model)
at System.Data.Entity.ModelConfiguration.Configuration.ModelConfiguration.ConfigureEntities(EdmModel model)
at System.Data.Entity.DbModelBuilder.Build(DbProviderManifest providerManifest, DbProviderInfo providerInfo)
at System.Data.Entity.DbModelBuilder.Build(DbConnection providerConnection)
at System.Data.Entity.Internal.LazyInternalContext.CreateModel(LazyInternalContext internalContext)
at System.Data.Entity.Internal.RetryLazy`2.GetValue(TInput input)
at System.Data.Entity.Internal.LazyInternalContext.InitializeContext()
at System.Data.Entity.Internal.InternalContext.GetEntitySetAndBaseTypeForType(Type entityType)
at System.Data.Entity.Internal.Linq.InternalSet`1.Initialize()
at System.Data.Entity.Internal.Linq.InternalSet`1.get_InternalContext()
at System.Data.Entity.Infrastructure.DbQuery`1.System.Linq.IQueryable.get_Provider()
at System.Linq.Queryable.FirstOrDefault[TSource](IQueryable`1 source)
... // my test query function

尝试改进#2

我想我可以将它们声明为抽象的，所以至少程序员必须实现正确的成员(在每个派生类上重新声明仍然很糟糕)：

public abstract class SharedFranchiseIdBase
{
[Key]
public int Id { get; set; }
public abstract FranchiseEntity Entity { get; set; }
public abstract FranchiseMiscellaneous Miscellaneous { get; set; }
}
public class Franchise : SharedFranchiseIdBase
{
[Key]
public int Id { get; set; }
public override FranchiseEntity Entity { get; set; }
public override FranchiseMiscellaneous Miscellaneous { get; set; }
}
//etc for other classes

但当出现同样的错误时，这会失败。嗯？？类定义与工作副本相同，只是它们被声明为"override"而不是"virtual"。就好像E/F在PropertyInfos或其他什么上进行索引而不考虑PropertyInfo.ReflectedType

尝试改进#3

我可以使用接口来强制执行模式，但这不太可取，因为接口必须在每个类上声明，这开始看起来很奇怪：

public class Franchise : SharedFranchiseIdBase, ISharedFranchiseId { ... }
public class FranchiseEntity : SharedFranchiseIdBase, ISharedFranchiseId { ... }
public class FranchiseMiscellaneous : SharedFranchiseIdBase, ISharedFranchiseId { ... }

嗯

这是E/F中的一个错误吗？它很难将基类上的属性与派生类上的属性相同？

对冗长的解释表示歉意，这是今天上午整个调查的总结。

Answer 1

最后，我决定采用手动解决方案，因为我无法进行任何改进尝试。

代码&模型并不优雅，但最终它的性能还可以。我已经在3个领域实现了该模式，并且它在域和SQL层按需运行。

为了减轻这种痛苦，并为开发人员提供一种一致的方式来处理这种模式，我创建了这个接口来强制执行所有关系：

public interface ISharedFranchiseId
{
FranchiseBilling Billing { get; set; }
FranchiseCompliance Compliance { get; set; }
FranchiseLeadAllocation LeadAllocation { get; set; }
FranchiseMessaging Messaging { get; set; }
FranchiseMiscellaneous Miscellaneous { get; set; }
FranchiseSignup Signup { get; set; }
}

因此，共享主键的每个模型都具有以下属性(令人讨厌的一点)：

public class FranchiseBilling/Compliance/etc : ISharedFranchiseId
{
// Properties implemented on this model
#region Navigations to other entities sharing primary key
public virtual FranchiseBilling Billing { get; set; }
public virtual FranchiseCompliance Compliance { get; set; }
public virtual FranchiseLeadAllocation LeadAllocation { get; set; }
public virtual FranchiseMessaging Messaging { get; set; }
public virtual FranchiseMiscellaneous Miscellaneous { get; set; }
public virtual FranchiseSignup Signup { get; set; }
#endregion
}

并通过Fluent API配置如下(痛苦的一点)：

// Franchise = the "primary/parent" model
public class FranchiseMapping : EntityTypeConfiguration<Franchise>
{
public FranchiseMapping()
{
HasRequired(x => x.Billing).WithRequiredPrincipal();
HasRequired(x => x.Compliance).WithRequiredPrincipal();
HasRequired(x => x.LeadAllocation).WithRequiredPrincipal();
HasRequired(x => x.Miscellaneous).WithRequiredPrincipal();
HasRequired(x => x.Messaging).WithRequiredPrincipal();
HasRequired(x => x.Signup).WithRequiredPrincipal();
}
}
// Now each "child" model gets link to all the others. We only need links going one way,
// So each model links to the ones listed below.
// This makes it easy to implement an extra child model down the track as we just
// insert the configuration it here and copy from the next one.
public class FranchiseBillingMapping : EntityTypeConfiguration<FranchiseBilling>
{
public FranchiseBillingMapping()
{
Ignore(x => x.Billing);
HasRequired(x => x.Compliance).WithRequiredDependent(x => x.Billing);
HasRequired(x => x.LeadAllocation).WithRequiredPrincipal(x => x.Billing);
HasRequired(x => x.Miscellaneous).WithRequiredPrincipal(x => x.Billing);
HasRequired(x => x.Messaging).WithRequiredPrincipal(x => x.Billing);
HasRequired(x => x.Signup).WithRequiredPrincipal(x => x.Billing);
}
}
public class FranchiseComplianceMapping : EntityTypeConfiguration<FranchiseCompliance>
{
public FranchiseComplianceMapping()
{
Ignore(x => x.Compliance);
HasRequired(x => x.LeadAllocation).WithRequiredPrincipal(x => x.Compliance);
HasRequired(x => x.Miscellaneous).WithRequiredPrincipal(x => x.Compliance);
HasRequired(x => x.Messaging).WithRequiredPrincipal(x => x.Compliance);
HasRequired(x => x.Signup).WithRequiredPrincipal(x => x.Compliance);
}
}
public class FranchiseLeadAllocationMapping : EntityTypeConfiguration<FranchiseLeadAllocation>
{
public FranchiseLeadAllocationMapping()
{
Ignore(x => x.LeadAllocation);
HasRequired(x => x.Miscellaneous).WithRequiredPrincipal(x => x.LeadAllocation);
HasRequired(x => x.Messaging).WithRequiredPrincipal(x => x.LeadAllocation);
HasRequired(x => x.Signup).WithRequiredPrincipal(x => x.LeadAllocation);
}
}
public class FranchiseeMiscellaneousMapping : EntityTypeConfiguration<FranchiseeMiscellaneous>
{
public FranchiseeMiscellaneousMapping()
{
Ignore(x => x.Miscellaneous);
HasRequired(x => x.Messaging).WithRequiredPrincipal(x => x.Miscellaneous);
HasRequired(x => x.Signup).WithRequiredPrincipal(x => x.Miscellaneous);
}
}
public class FranchiseMessagingMapping : EntityTypeConfiguration<FranchiseMessaging>
{
public FranchiseMessagingMapping()
{
Ignore(x => x.Messaging);
HasRequired(x => x.Signup).WithRequiredPrincipal(x => x.Messaging);
}
}
public class FranchiseSignupMapping : EntityTypeConfiguration<FranchiseSignup>
{
public FranchiseSignupMapping()
{
Ignore(x => x.Signup);
}
}