EF 不更新相关实体，只更新简单字段

Question

我在 EF 6.1 中使用 codeFirst 和独立关联 EF 不会更新分离的实体。 Attach 和 StateModified 对 Related(FK) 实体没有帮助。添加新实体和更新不相关的属性可以正常工作。问题出在哪里？

我有主要实体 CoachTransaction :

public class CoachTransaction : BaseEntity
    {
        public DateTime? TransactionDate { get; set; }

        public int? Season { get; set; }
        public virtual CoachPosition Position { get; set; }
        public virtual Institution StartInstitution { get; set; }
        public virtual Institution EndInstitution { get; set; }       
    }

它的映射：

public MapCoachTransaction()
        {
            ToTable("CoachTransactions");
            HasKey(x => x.Id);

            Property(x => x.Id).HasColumnName("TransactionId");
            Property(x => x.TransactionDate);

            HasOptional(x => x.Position).WithMany().Map(x => x.MapKey("CoachPositionId"));
            HasOptional(x => x.StartInstitution).WithMany().Map(x => x.MapKey("StartInstitutionId"));
            HasOptional(x => x.EndInstitution).WithMany().Map(x => x.MapKey("EndInstitutionId"));
        }

相关实体的映射：

 public MapInstitution()
        {
            ToTable("Institution");
            HasKey(x => x.Id);
            Property(x => x.Id).HasColumnName("InstitutionId");
            HasOptional(x => x.InstitutionType).WithMany(x => x.Institutions).Map(x => x.MapKey("InstitutionTypeId"));
            Property(x => x.Name).HasColumnName("InstitutionName");
            Property(x => x.ImageUrl).HasColumnName("InstitutionImageUrl");
        }

用法是这样的：

                using (var context = new CoachDBContext())
                {
                    IGenericRepository<CoachTransaction> repository = new GenericRepository<CoachTransaction>(context);
                   coachTransaction.Seasion = 100; // this works
                    coachTransaction.EndInstitution = newInstitution; this doesnt'
                    repository.Update(coachTransaction); // coachTransaction comes from POST to Controller
                    repository.Save();
                }

和 repository.Updarte 方法当然使用 Attach:

public virtual void Update(TEntity entityToUpdate)
        {
            EntitySet.Attach(entityToUpdate);
            dbContext.Entry(entityToUpdate).State = EntityState.Modified;
        }

使用此设置，SQL 请求如下所示：

exec sp_executesql N'UPDATE [dbo].[CoachTransactions]
SET [TransactionDate] = @0, [Season] = @1
WHERE ([TransactionId] = @2)
',N'@0 datetime2(7),@1 int,@2 int',@0='2015-04-21 20:40:38.1840996',@1=100,@2=24

因此，没有要更新的 endInstitution 实体。

但是如果我在保存前请求这个实体：

  using (var context = new CoachDBContext())
                    {
                        IGenericRepository<CoachTransaction> repository = new GenericRepository<CoachTransaction>(context);
                        var coachTransaction = repository.GetById(coachTransaction.Id) // this fixes problem, but not acceptable in this case
                        coachTransaction.Season = 100; 
                        coachTransaction.EndInstitution = newInstitution; // now this will work
                        repository.Update(coachTransaction); // coachTransaction comes from POST to Controller
                        repository.Save();
                    }

并且 SQL 将包含相关键，例如：

exec sp_executesql N'UPDATE [dbo].[CoachTransactions]
SET [TransactionDate] = @0, [Season] = @1, 

[EndInstitution] = @2

WHERE ([TransactionId] = @3)
',N'@0 datetime2(7),@1 int,@2 int, @3 int',@0='2015-04-21 20:40:38.1840996',@1=100,@2=2,@3=24

P.S.

此外，外键关联方法的使用解决了这个映射问题：

Property(x => x.PositionId).HasColumnName("CoachPositionId");
            Property(x => x.StartInstitutionId).HasColumnName("StartInstitutionId");
            Property(x => x.EndInstitutionId).HasColumnName("EndInstitutionId");
            HasRequired(x => x.Position).WithMany().HasForeignKey(x => x.PositionId);
            HasRequired(x => x.StartInstitution).WithMany().HasForeignKey(x => x.StartInstitutionId);
            HasRequired(x => x.EndInstitution).WithMany().HasForeignKey(x => x.EndInstitutionId);

但这会导致另一个问题，当我在更新相关实体时必须设置两个属性而不是一个属性，例如：

updatingObject.EndInstitution = existingInstitution2; 
updatingObject.EndInstitutionId = existingInstitution2.Id;

而不是一个电话： updatingObject.EndInstitution = existingInstitution2;

它还需要无用的 Id 属性。从我的角度来看，这看起来是错误的。有什么解决办法吗？

Answer 1

Attach 方法不附加子实体。为此，您需要附加所有要更新的从属目标。您可以使用 GraphDiff 来更新完整图表而不附加实体。用法是这样的：使用 (var con

text = new TestDbContext())  
{
    // Update the company and state that the company 'owns' the collection Contacts.
    context.UpdateGraph(company, map => map
        .OwnedCollection(p => p.Contacts, with => with
            .AssociatedCollection(p => p.AdvertisementOptions))
        .OwnedCollection(p => p.Addresses)
    );

    context.SaveChanges();
}

这是框架的 brief introduction。

此外，我一直在查看 Entity Framework 的源代码并找到了一种方法来实际更新实体，如果你知道密钥属性在另一种情况下你需要检查 AddOrUpdate 实现:

public void Update(T item)
{
    var entity = _collection.Find(item.Id);
    if (entity == null)
    {
        return;
    }

    _context.Entry(entity).CurrentValues.SetValues(item);
}

希望对您有所帮助！

EF 不更新相关实体，只更新简单字段

EF doesn't updated related entities, only simple fields

.net

c#

mapping

entity-framework