添加具有許多關系的擁有物體導致并發例外由于更新而不是插入

我有一個問題，添加擁有的物體會導致 EF Core 發出UPDATE陳述句而不是INSERT，從而導致并發例外。

我有以下課程（簡化以使問題更短）：

public abstract class PaymentDemand
{
   public Guid Id { get; set; }

   public SettlementTransactions? SettlementTransactions { get; set; }
    // And more properties
}

public class SettlementTransactions
{
   public List<SettlementAllowance> ConsumedAllowances { get; set; } = new List<SettlementAllowance>();
   public List<SettlementCharge> GeneratedCharges { get; set; } = new List<SettlementCharge>();
}

public class SettlementAllowance
{
    public Guid PaymentDemandId { get; set; }

    /// <summary>The type of the transaction.</summary>
    public string TransactionType { get; set; }
    // And more properties
}

然后我設定了付款需求：

public void Configure(EntityTypeBuilder<PaymentDemand> builder)
{
        builder.HasKey(p => p.Id);
        builder.Property(p => p.Id).ValueGeneratedNever();

        builder.OwnsOne(p => p.SettlementTransactions, transactionBuilder =>
        {
            transactionBuilder.OwnsMany(a => a.ConsumedAllowances, allowanceBuilder =>
            {
                allowanceBuilder.WithOwner().HasForeignKey(t => t.PaymentDemandId);
                allowanceBuilder.HasKey(p => p.AccountTransactionId);
                allowanceBuilder.Property(p => p.Amount).HasColumnType("Money");
                allowanceBuilder.ToTable("SettlementAllowances");
            });

            transactionBuilder.OwnsMany(c => c.GeneratedCharges, chargesBuilder =>
            {
                chargesBuilder.WithOwner().HasForeignKey(t => t.PaymentDemandId);
                chargesBuilder.HasKey(p => p.AccountTransactionId);
                chargesBuilder.Property(p => p.AccountTransactionId).ValueGeneratedNever();
                chargesBuilder.Property(p => p.Amount).HasColumnType("Money");
                chargesBuilder.ToTable("SettlementCharges");
            });
        });

        builder.Navigation(t => t.SettlementTransactions).IsRequired();
}

最后，我有進行保存的代碼。

public async Task DoThings(DbContext context)
{
        var demand = await context.PaymentDemands
            .Include(st => st.SettlementTransactions)
            .FirstOrDefaultAsync(d => d.Id == id, default);

        if (demand == null)
        {
            throw new InvalidOperationException();
        }

        demand.SettleDate = DateTime.UtcNow;
        demand.SettlementTransactions ??= new SettlementTransactions();
        demand.SettlementTransactions.ConsumedAllowances.Add(new SettlementAllowance{ TransactionType = "Blah" });
        await context.SaveChangesAsync(); // THROWS.
}

更改跟蹤器似乎正在確定它應該做什么（來自日志）：

DetectChanges starting for 'SqlBillingContext'.
      2 entities were added and 0 entities were removed from navigation 'SettlementTransactions.ConsumedAllowances' on entity with key '{PaymentDemandId: d00544fe-c6c5-4b1d-a438-81508332af2d}'.
      Context 'SqlBillingContext' started tracking 'SettlementAllowance' entity with key '{AccountTransactionId: 296596b3-d45d-4753-b2f5-0ba7566f6800}'.
      Context 'SqlBillingContext' started tracking 'SettlementAllowance' entity with key '{AccountTransactionId: 7395965f-7fda-46d9-9e3b-3b428d4a7dce}'.

但由于某種原因，它最終會在更新之后結束：

      Executing update commands individually as the number of batchable commands (2) is smaller than the minimum batch size (4).
      Executing DbCommand [Parameters=[@p11='296596b3-d45d-4753-b2f5-0ba7566f6800', @p0='2022-10-25T09:34:41.7143804 00:00', @p1='49.5' (Precision = 3) (Scale = 1), @p2=NULL (Size = 4000), @p3='2022-12-24T09:18:36.3176378 00:00' (Nullable = true), @p4='6ca8c244-4438-4476-b417-ed501c378c0e' (Nullable = true), @p5='12032' (Nullable = true), @p6='d00544fe-c6c5-4b1d-a438-81508332af2d', @p7='df99b62b-d1b6-4d58-8c69-4df7eef33b61' (Nullable = true), @p8='d00544fe-c6c5-4b1d-a438-81508332af2d' (Nullable = true), @p9='2022-11-24T09:18:37.3176378 00:00' (Nullable = true), @p10='1'], CommandType='Text', CommandTimeout='30']

      SET NOCOUNT ON;
      UPDATE [SettlementAllowances] SET [AccountingTime] = @p0, [Amount] = @p1, [Description] = @p2, [EndTime] = @p3, [InvoiceId] = @p4, [InvoiceNumber] = @p5, [PaymentDemandId] = @p6, [PaymentId] = @p7, [SourcePaymentDemandId] = @p8, [StartTime] = @p9, [TransactionType] = @p10
      WHERE [AccountTransactionId] = @p11;
      SELECT @@ROWCOUNT;

我真的不明白這里發生了什么。有什么建議、想法或明顯的原因導致這不能像我希望的那樣作業嗎？

uj5u.com熱心網友回復：

通常情況下，寫這些帖子幾乎就像橡皮擦一樣。

我的問題是我有我創建的物體的主鍵（因為我基本上是在移動它）。因此 EF 認為它需要生成一個不存在的密鑰，并且提供了一個，它假定記錄存在（默認行為）。

解決方案是簡單地添加 NEVER 的生成策略：

allowancesBuilder.Property(p => p.AccountTransactionId).ValueGeneratedNever();

我已經對費用和付款了！

默認顯然是ValueGeneratedSometimes....

標籤：实体框架实体框架核心

上一篇：按今天的日期過濾Firestore查詢

下一篇：如何在ASP.NETCore中自定義默認AspNetUsers資料型別長度