c# - 如何正确定义 EF Core 创建的这些类之间的关系?
问题描述
首先道歉,这是一个菜鸟问题。
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。(我知道这听起来可能是个坏主意,但我们有自己的理由……)我决定使用 ef core 连接到数据库。
我曾经Scaffold-DbContext
将数据库结构放入我的程序中。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:
System.InvalidOperationException: '无法确定'Dad.DadCmu'和'DadCmu.IddadNavigation'之间的一对一关系的子/依赖方。要识别关系的子/依赖方,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,请在不指定反向的情况下配置它们。有关详细信息,请参阅http://go.microsoft.com/fwlink/?LinkId=724062 。
所以我猜这种关系没有很好地定义。那么让我们看看这些类:
public partial class DadCmu
{
public int Iddad { get; set; }
public byte UnitNo { get; set; }
public virtual Dad IddadNavigation { get; set; }
}
所以 IddadNavigation 是 Dad 类型:
public partial class Dad
{
public Dad()
{
DadCh = new HashSet<DadCh>();
DadConnection = new HashSet<DadConnection>();
}
public int Iddad { get; set; }
public string Name { get; set; }
public int? DadType { get; set; }
public short? Active { get; set; }
public DateTime? LastUpdate { get; set; }
public byte? SynchronizationStatus { get; set; }
public virtual DadCmu DadCmu { get; set; }
public virtual DadMasCon DadMasCon { get; set; }
public virtual DadOpc DadOpc { get; set; }
public virtual ICollection<DadCh> DadCh { get; set; }
public virtual ICollection<DadConnection> DadConnection { get; set; }
}
他们的关系应该定义在OnModelCreating
:
protected override void OnModelCreating(ModelBuilder modelBuilder)
{
…
modelBuilder.Entity<DadCmu>(entity =>
{
entity.HasKey(e => e.Iddad);
entity.ToTable("DadCMU");
entity.Property(e => e.Iddad)
.HasColumnName("IDDad")
.ValueGeneratedNever();
entity.HasOne(d => d.IddadNavigation)
.WithOne(p => p.DadCmu)
.HasForeignKey<DadCmu>(d => d.Iddad)
.HasConstraintName("FK_DadCMU_Dad");
});
…
modelBuilder.Entity<Dad>(entity =>
{
entity.HasKey(e => e.Iddad);
entity.Property(e => e.Iddad).HasColumnName("IDDad");
entity.Property(e => e.LastUpdate).HasColumnType("datetime");
});
…
}
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?我必须在内部做同样的事情modelBuilder.Entity<Dad>
吗?
那个代码会是什么样子?
还是我完全误解了这个问题?
这是可以自动完成的,例如使用参数 forscaffold-dbcontext
吗?(我的数据库有 180 个表,其中许多表都出现相同的错误。)
在不改变数据库本身结构的情况下,这一切都可能吗?
非常感谢您提前!同样,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。
编辑: 在评论中出现的类 DadOpc:
public partial class DadOpc
{
public int Iddad { get; set; }
public string Computer { get; set; }
public string OpcserviceName { get; set; }
public float? ScanInterval { get; set; }
public byte? ServerType { get; set; }
public byte? UseSecurity { get; set; }
public virtual Dad IddadNavigation { get; set; }
}
编辑 2:(关于 jcruz 的解决方案)
错误信息:
System.InvalidOperationException: '无法确定'DadMasCon.IddadNavigation'和'Dad.DadMasCon'之间的一对一关系的子/依赖方。要识别关系的子/依赖方,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,请在不指定反向的情况下配置它们。有关详细信息,请参阅http://go.microsoft.com/fwlink/?LinkId=724062 。
爸爸班:
public partial class Dad
{
public Dad()
{
DadCh = new HashSet<DadCh>();
DadConnection = new HashSet<DadConnection>();
}
//user added Id-Fields:
public int DadCmuId { get; set; }
public int DadOpcId { get; set; }
public int DadMasConId { get; set; }
public int Iddad { get; set; }
public string Name { get; set; }
public int? DadType { get; set; }
public short? Active { get; set; }
public DateTime? LastUpdate { get; set; }
public byte? SynchronizationStatus { get; set; }
public virtual DadCmu DadCmu { get; set; }
public virtual DadMasCon DadMasCon { get; set; }
public virtual DadOpc DadOpc { get; set; }
public virtual ICollection<DadCh> DadCh { get; set; }
public virtual ICollection<DadConnection> DadConnection { get; set; }
}
类DadMasCon:
public DadMasCon()
{
DadModbusRegConfig = new HashSet<DadModbusRegConfig>();
}
public int Iddad { get; set; }
public int UnitNo { get; set; }
public byte? Model { get; set; }
public DateTime? RefTimeOffset { get; set; }
public float? TimeoutComm { get; set; }
public int? Port { get; set; }
public float? ConnectionInterval { get; set; }
public byte? ExternalComm { get; set; }
public string Mvbparameters { get; set; }
public byte? ModbusBps { get; set; }
public byte? ModbusParity { get; set; }
public byte? ModbusStopBits { get; set; }
public byte? ModbusMode { get; set; }
public byte? ModbusSlaveAddress { get; set; }
public byte? CardType0 { get; set; }
public byte? CardType1 { get; set; }
public byte? CardType2 { get; set; }
public byte? CardType3 { get; set; }
public string LastIp { get; set; }
public string HiddenParameter { get; set; }
public int? SerialNo { get; set; }
public int? LastSequence { get; set; }
public int? TcppackageErrors { get; set; }
public byte? UsePrivateFirmware { get; set; }
public byte? ConfigurationLock { get; set; }
public byte? IecclientOn { get; set; }
public string IecclientAddress { get; set; }
public string IecclientDomain { get; set; }
public byte? IecsrvOn { get; set; }
public byte? IecsrvNrOfClents { get; set; }
public string IecsrvAuthentication { get; set; }
public string Iecmmsparam { get; set; }
public float? IecclientPollInterval { get; set; }
public byte? NtpserverType { get; set; }
public string Ntpipaddress { get; set; }
public string IecmmsparamFileName { get; set; }
public string ModbusTcpaddress { get; set; }
public int? ModbusTcpportNr { get; set; }
public byte? ModbusByteOrder { get; set; }
public byte? ModbusClientValueType { get; set; }
public string Macaddress { get; set; }
public byte? MonitorInitiate { get; set; }
public virtual Dad IddadNavigation { get; set; }
public virtual ICollection<DadModbusRegConfig> DadModbusRegConfig { get; set; }
}
OnModelCreating:
modelBuilder.Entity<DadMasCon>(entity =>
{
entity.HasKey(e => e.Iddad)
.HasName("PK_DadMasCon16");
entity.Property(e => e.Iddad)
.HasColumnName("IDDad")
.ValueGeneratedNever();
entity.Property(e => e.IecclientAddress).HasColumnName("IECClientAddress");
entity.Property(e => e.IecclientDomain).HasColumnName("IECClientDomain");
entity.Property(e => e.IecclientOn).HasColumnName("IECClientOn");
entity.Property(e => e.IecclientPollInterval).HasColumnName("IECClientPollInterval");
entity.Property(e => e.Iecmmsparam).HasColumnName("IECMMSParam");
entity.Property(e => e.IecmmsparamFileName).HasColumnName("IECMMSParamFileName");
entity.Property(e => e.IecsrvAuthentication).HasColumnName("IECSrvAuthentication");
entity.Property(e => e.IecsrvNrOfClents).HasColumnName("IECSrvNrOfClents");
entity.Property(e => e.IecsrvOn).HasColumnName("IECSrvOn");
entity.Property(e => e.Macaddress).HasColumnName("MACAddress");
entity.Property(e => e.ModbusTcpaddress)
.HasColumnName("ModbusTCPAddress")
.HasMaxLength(50);
entity.Property(e => e.ModbusTcpportNr).HasColumnName("ModbusTCPPortNr");
entity.Property(e => e.Mvbparameters).HasColumnName("MVBParameters");
entity.Property(e => e.Ntpipaddress).HasColumnName("NTPIPAddress");
entity.Property(e => e.NtpserverType).HasColumnName("NTPServerType");
entity.Property(e => e.RefTimeOffset).HasColumnType("datetime");
entity.Property(e => e.TcppackageErrors).HasColumnName("TCPPackageErrors");
//user generated:
entity.HasOne(d => d.IddadNavigation)
.WithOne(p => p.DadMasCon)
.HasForeignKey<Dad>(d => d.DadMasConId);
//original:
//entity.HasOne(d => d.IddadNavigation)
// .WithOne(p => p.DadMasCon)
// .HasForeignKey<DadMasCon>(d => d.Iddad)
// .HasConstraintName("FK_DadMasCon_Dad");
});
解决方案
由于您尝试定义一对一的关系,因此您需要在Dad
模型上显式定义反向引用 id,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);
});
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