如何正确定义 EF Core 创建的这些类之间的关系？

Question

首先抱歉，这是一个菜鸟问题。

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我正在尝试编写连接到现有数据库并根据用户输入更改某些值的 ac# 程序。（我知道这听起来像是一个坏主意，但我们有我们的理由\xe2\x80\xa6）我决定使用 ef core 连接到数据库。

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我曾经Scaffold-DbContext将数据库结构放入我的程序中。\n构建成功，但是每当我尝试运行我的程序时，我都会收到以下错误消息：

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System.InvalidOperationException： \'无法确定\'Dad.DadCmu\'和\'DadCmu.IddadNavigation\'之间的一对一关系的子/从属方。要识别关系的子方/从属方，请配置外键属性。如果这些导航不应该是同一关系的一部分，则配置它们而不指定相反关系。有关更多详细信息，请参阅http://go.microsoft.com/fwlink/ ?LinkId=724062。\'

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所以我猜这种关系没有明确定义。让我们看看这些类：

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    public partial class DadCmu\n    {\n        public int Iddad { get; set; }\n        public byte UnitNo { get; set; }\n\n        public virtual Dad IddadNavigation { get; set; }\n    }\n

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所以 IddadNavigation 是 Dad 类型：

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public partial class Dad\n    {\n        public Dad()\n        {\n            DadCh = new HashSet<DadCh>();\n            DadConnection = new HashSet<DadConnection>();\n        }\n\n        public int Iddad { get; set; }\n        public string Name { get; set; }\n        public int? DadType { get; set; }\n        public short? Active { get; set; }\n        public DateTime? LastUpdate { get; set; }\n        public byte? SynchronizationStatus { get; set; }\n\n        public virtual DadCmu DadCmu { get; set; }\n        public virtual DadMasCon DadMasCon { get; set; }\n        public virtual DadOpc DadOpc { get; set; }\n        public virtual ICollection<DadCh> DadCh { get; set; }\n        public virtual ICollection<DadConnection> DadConnection { get; set; }\n    }\n

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他们的关系应该定义在OnModelCreating：

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protected override void OnModelCreating(ModelBuilder modelBuilder)\n        {\n        \xe2\x80\xa6\n        modelBuilder.Entity<DadCmu>(entity =>\n            {\n                entity.HasKey(e => e.Iddad);\n\n                entity.ToTable("DadCMU");\n\n                entity.Property(e => e.Iddad)\n                    .HasColumnName("IDDad")\n                    .ValueGeneratedNever();\n\n                entity.HasOne(d => d.IddadNavigation)\n                    .WithOne(p => p.DadCmu)\n                    .HasForeignKey<DadCmu>(d => d.Iddad)\n                    .HasConstraintName("FK_DadCMU_Dad");\n            });\n        \xe2\x80\xa6\n        modelBuilder.Entity<Dad>(entity =>\n            {\n                entity.HasKey(e => e.Iddad);\n\n                entity.Property(e => e.Iddad).HasColumnName("IDDad");\n\n                entity.Property(e => e.LastUpdate).HasColumnType("datetime");\n            });\n        \xe2\x80\xa6\n        }\n

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所以这里modelBuilder.Entity<DadCmu>确实明确提到了一个外键，所以我不太确定问题是什么？\n我必须在 中做同样的事情吗modelBuilder.Entity<Dad>？

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该代码会是什么样子？

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或者我完全误解了这个问题？

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这是可以自动完成的事情，例如使用参数 for 吗scaffold-dbcontext？（我的数据库有 180 个表，其中许多表都出现相同的错误。）

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这一切都可以在不改变数据库本身结构的情况下实现吗？

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提前非常感谢！再说一次，这是我第一次使用数据库，所以如果这真的很明显，我深表歉意。

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编辑： \nDadOpc 类出现在评论中：

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    public partial class DadOpc\n    {\n        public int Iddad { get; set; }\n        public string Computer { get; set; }\n        public string OpcserviceName { get; set; }\n        public float? ScanInterval { get; set; }\n        public byte? ServerType { get; set; }\n        public byte? UseSecurity { get; set; }\n\n        public virtual Dad IddadNavigation { get; set; }\n    }\n

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编辑2：（关于jcruz'解决方案）

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错误信息：

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System.InvalidOperationException： \'无法确定\'DadMasCon.IddadNavigation\'和\'Dad.DadMasCon\'之间的一对一关系的子/从属方。要识别关系的子方/从属方，请配置外键属性。如果这些导航不应该是同一关系的一部分，则配置它们而不指定相反关系。请参阅http://go.microsoft.com/fwlink/?LinkId=724062有关更多详细信息，

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班爸爸：

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public partial class Dad\n    {\n        public Dad()\n        {\n            DadCh = new HashSet<DadCh>();\n            DadConnection = new HashSet<DadConnection>();\n        }\n\n        //user added Id-Fields:\n        public int DadCmuId { get; set; }\n        public int DadOpcId { get; set; }\n        public int DadMasConId { get; set; }\n\n\n        public int Iddad { get; set; }\n        public string Name { get; set; }\n        public int? DadType { get; set; }\n        public short? Active { get; set; }\n        public DateTime? LastUpdate { get; set; }\n        public byte? SynchronizationStatus { get; set; }\n\n        public virtual DadCmu DadCmu { get; set; }\n        public virtual DadMasCon DadMasCon { get; set; }\n        public virtual DadOpc DadOpc { get; set; }\n        public virtual ICollection<DadCh> DadCh { get; set; }\n        public virtual ICollection<DadConnection> DadConnection { get; set; }\n    }\n

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爸爸马斯康班：

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        public DadMasCon()\n        {\n            DadModbusRegConfig = new HashSet<DadModbusRegConfig>();\n        }\n\n        public int Iddad { get; set; }\n        public int UnitNo { get; set; }\n        public byte? Model { get; set; }\n        public DateTime? RefTimeOffset { get; set; }\n        public float? TimeoutComm { get; set; }\n        public int? Port { get; set; }\n        public float? ConnectionInterval { get; set; }\n        public byte? ExternalComm { get; set; }\n        public string Mvbparameters { get; set; }\n        public byte? ModbusBps { get; set; }\n        public byte? ModbusParity { get; set; }\n        public byte? ModbusStopBits { get; set; }\n        public byte? ModbusMode { get; set; }\n        public byte? ModbusSlaveAddress { get; set; }\n        public byte? CardType0 { get; set; }\n        public byte? CardType1 { get; set; }\n        public byte? CardType2 { get; set; }\n        public byte? CardType3 { get; set; }\n        public string LastIp { get; set; }\n        public string HiddenParameter { get; set; }\n        public int? SerialNo { get; set; }\n        public int? LastSequence { get; set; }\n        public int? TcppackageErrors { get; set; }\n        public byte? UsePrivateFirmware { get; set; }\n        public byte? ConfigurationLock { get; set; }\n        public byte? IecclientOn { get; set; }\n        public string IecclientAddress { get; set; }\n        public string IecclientDomain { get; set; }\n        public byte? IecsrvOn { get; set; }\n        public byte? IecsrvNrOfClents { get; set; }\n        public string IecsrvAuthentication { get; set; }\n        public string Iecmmsparam { get; set; }\n        public float? IecclientPollInterval { get; set; }\n        public byte? NtpserverType { get; set; }\n        public string Ntpipaddress { get; set; }\n        public string IecmmsparamFileName { get; set; }\n        public string ModbusTcpaddress { get; set; }\n        public int? ModbusTcpportNr { get; set; }\n        public byte? ModbusByteOrder { get; set; }\n        public byte? ModbusClientValueType { get; set; }\n        public string Macaddress { get; set; }\n        public byte? MonitorInitiate { get; set; }\n\n        public virtual Dad IddadNavigation { get; set; }\n        public virtual ICollection<DadModbusRegConfig> DadModbusRegConfig { get; set; }\n    }\n

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模型创建时：

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modelBuilder.Entity<DadMasCon>(entity =>\n            {\n                entity.HasKey(e => e.Iddad)\n                    .HasName("PK_DadMasCon16");\n\n                entity.Property(e => e.Iddad)\n                    .HasColumnName("IDDad")\n                    .ValueGeneratedNever();\n\n                entity.Property(e => e.IecclientAddress).HasColumnName("IECClientAddress");\n\n                entity.Property(e => e.IecclientDomain).HasColumnName("IECClientDomain");\n\n                entity.Property(e => e.IecclientOn).HasColumnName("IECClientOn");\n\n                entity.Property(e => e.IecclientPollInterval).HasColumnName("IECClientPollInterval");\n\n                entity.Property(e => e.Iecmmsparam).HasColumnName("IECMMSParam");\n\n                entity.Property(e => e.IecmmsparamFileName).HasColumnName("IECMMSParamFileName");\n\n                entity.Property(e => e.IecsrvAuthentication).HasColumnName("IECSrvAuthentication");\n\n                entity.Property(e => e.IecsrvNrOfClents).HasColumnName("IECSrvNrOfClents");\n\n                entity.Property(e => e.IecsrvOn).HasColumnName("IECSrvOn");\n\n                entity.Property(e => e.Macaddress).HasColumnName("MACAddress");\n\n                entity.Property(e => e.ModbusTcpaddress)\n                    .HasColumnName("ModbusTCPAddress")\n                    .HasMaxLength(50);\n\n                entity.Property(e => e.ModbusTcpportNr).HasColumnName("ModbusTCPPortNr");\n\n                entity.Property(e => e.Mvbparameters).HasColumnName("MVBParameters");\n\n                entity.Property(e => e.Ntpipaddress).HasColumnName("NTPIPAddress");\n\n                entity.Property(e => e.NtpserverType).HasColumnName("NTPServerType");\n\n                entity.Property(e => e.RefTimeOffset).HasColumnType("datetime");\n\n                entity.Property(e => e.TcppackageErrors).HasColumnName("TCPPackageErrors");\n\n                //user generated:\n                entity.HasOne(d => d.IddadNavigation)\n                    .WithOne(p => p.DadMasCon)\n                    .HasForeignKey<Dad>(d => d.DadMasConId);\n\n                //original:\n                //entity.HasOne(d => d.IddadNavigation)\n                //    .WithOne(p => p.DadMasCon)\n                //    .HasForeignKey<DadMasCon>(d => d.Iddad)\n                //    .HasConstraintName("FK_DadMasCon_Dad");\n            });\n

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Answer 1

由于您尝试定义一对一关系，因此您需要在模型上显式定义反向引用 id，Dad以确保它映射到单个DadCmu记录。

public partial class Dad
{
    public int DadCmuId { get; set; }
    public virtual DadCmu DadCmu { get; set; }
}

然后您可以使用 Fluent API 进行配置，如下所示：

modelBuilder.Entity<DadCmu>(entity =>
{
    entity.HasOne(d => d.IddadNavigation)
          .WithOne(p => p.DadCmu)
          .HasForeignKey<Dad>(d => d.DadCmuId);
});

华泰