EF Core 2.1 对自有类型的更改是什么？

Question

Docs 最后更改于 2018 年 2 月 26 日，但我需要修复一些重大更改。

我有MyProcessContext 类型，用作许多实体的所有：

public class RequestData
{
    public Guid CorrelationId { get; set; }
    public DateTime Updated { get; set; }

    public MyProcessContext ProcessContext { get; set; }
}

public class MyProcessContext
{
    public int ClientId { get; set; }
}

public class EntityConfiguration : IEntityTypeConfiguration<RequestData>
{
    public void Configure(EntityTypeBuilder<RequestData> builder)
    {
        // all mapped by convention

        builder.OwnsOne(x => x.ProcessContext);

        builder.Property(x => x.Updated).IsRowVersion();

        builder.HasKey(x => x.CorrelationId);
        builder.Property(x => x.CorrelationId).ValueGeneratedNever();
    }
}

它在 EF Core 2.0 中按预期工作。在调试视图中，对于自有类型 (RequestData.ProcessContext#MyProcessContext) 的每种用法，我都有不同的实体类型：

  EntityType: RequestData
    Properties: 
      CorrelationId (Guid) Required PK AfterSave:Throw 0 0 0 -1 -1
        Annotations: 
          Relational:ColumnName: correlation_id      
      Updated (DateTime) Required Concurrency BeforeSave:Ignore AfterSave:Ignore ValueGenerated.OnAddOrUpdate 11 11 -1 -1 0
        Annotations: 
          Relational:ColumnName: updated
    Navigations: 
      ProcessContext (<ProcessContext>k__BackingField, MyProcessContext) ToDependent RequestData.ProcessContext#MyProcessContext 0 -1 1 -1 -1
    Keys: 
      CorrelationId PK
    Annotations: 
      Relational:TableName: process_request
      RelationshipDiscoveryConvention:NavigationCandidates: System.Collections.Immutable.ImmutableSortedDictionary`2[System.Reflection.PropertyInfo,System.Type]

  EntityType: RequestData.ProcessContext#MyProcessContext
    Properties: 
      RequestDataCorrelationId (no field, Nullable<Guid>) Shadow Required PK FK AfterSave:Throw 0 0 0 0 -1
      ClientId (int) Required 1 1 -1 -1 -1      
    Keys: 
      RequestDataCorrelationId PK
    Foreign keys: 
      RequestData.ProcessContext#MyProcessContext {'RequestDataCorrelationId'} -> RequestData {'CorrelationId'} Unique ToDependent: ProcessContext
    Annotations: 
      Relational:TableName: process_request
      RelationshipDiscoveryConvention:NavigationCandidates: System.Collections.Immutable.ImmutableSortedDictionary`2[System.Reflection.PropertyInfo,System.Type]    

升级后调试视图包含

  EntityType: RequestData
      ...
      ProcessContext (<ProcessContext>k__BackingField, MyProcessContext) ToDependent MyProcessContext 0 -1 1 -1 -1
      ...
  EntityType: MyProcessContext
    Properties: 
      RequestDataCorrelationId (no field, Guid) Shadow Required PK FK AfterSave:Throw 0 0 0 0 -1
      ClientId (int) Required 1 1 -1 -1 -1
    Keys: 
      RequestDataCorrelationId PK
    Foreign keys: 
      MyProcessContext {'RequestDataCorrelationId'} -> RequestData {'CorrelationId'} Unique Ownership ToDependent: ProcessContext
    Annotations: 
      Relational:TableName: process_request
      RelationshipDiscoveryConvention:NavigationCandidates: System.Collections.Immutable.ImmutableSortedDictionary`2[System.Reflection.PropertyInfo,System.Type]

像MyProcessContext 这样构建的模型是通常的实体。在像

这样的代码中

foreach (var entity in modelBuilder.Model.GetEntityTypes())
            {
                var entityIsOwned = entity.IsOwned();

entityIsOwned 为真，但entity.DefiningNavigationName 现在为空。

我需要 custom name convention 的名称。

Answer 1

到目前为止，唯一的官方更改（EF Core 2.1）是添加了[Owned] Attribute。

但是显然在实现中存在重大变化，因此DefiningEntityType 和DefiningNavigationName 属性不再可靠（无论如何它们都没有记录 - 只是“标准”生成无用“获取定义实体类型。 " 和 "获取定义导航的名称。")。

通过实验，我发现只有在拥有的类型用于多个实体时才会填充它们。不知道他们为什么这样做，但重点是我们不应该使用它们，而且 EF Core 代码本身似乎也不再使用它们了。

据我所知，IsOwned、DefiningEntityType 和 DefiningNavigationName 术语由具有等于 true 的 IsOwnership 属性的外键确定。

换句话说：

var ownershipFk = entityType.GetForeignKeys().FirstOrDefault(fk => fk.IsOwnership);
var isOwned = ownershipFk != null;
var definingEntityType = ownershipFk?.PrincipalEntityType;
var definingNavigationName = ownershipFk?.PrincipalToDependent.Name;