将表的每个层次结构继承用于1：2关系

debugcn 发表于 Dev

沙巴玛凯

我的以下Jobcard课程有两个小节MechanicalJobcard，PanelbeatingJobcard

public abstract class Jobcard : Entity, IAggregateRoot
{
    public int VehicleId { get; private set; }
    public int JobcardTypeId { get; protected set; }
    public string Opened_By { get; private set; } //TODO Identity Sever
    public DateTime Open_Date { get; private set; }
    public Vehicle Vehicle { get; private set; }
    public JobcardType JobcardType { get; private set; }

    public Jobcard()
    {
        Opened_By = "Job card opener";
        Open_Date = DateTime.Now;
    }
}
public class PanelBeatingJobcard : Jobcard
{
    public PanelBeatingJobcard()
    {
        JobcardTypeId = 1;
    }
}

public class MechanicalJobcard: Jobcard
{
    public MechanicalJobcard()
    {
        JobcardTypeId = 2;
    }
}

我有一个车辆的既有MechanicalJobcard和PanelbeatingJobcard

public class Vehicle: Entity, IAggregateRoot
{
    public int Id{ get; set; }
   //Other properties here...

    public PanelBeatingJobcard PanelBeatingJobcard { get; set; }
    public MechanicalJobcard MechanicalJobcard { get; set; }
}

我似乎可以使用流畅的API将它们映射到数据库。

我试过了

class PanelBeatingJobCardEntityTypeConfiguration: IEntityTypeConfiguration<PanelBeatingJobcard>
{
    public void Configure(EntityTypeBuilder<PanelBeatingJobcard> panelBeatinglJobcardConfig)
    {
        panelBeatinglJobcardConfig.HasOne(j => j.Vehicle).WithOne(v => v.PanelBeatingJobcard).HasForeignKey<Jobcard>(j => j.VehicleId);
    }
}
class MechanicalJobcardEntityTypeConfiguration: IEntityTypeConfiguration<MechanicalJobcard>
{
    public void Configure(EntityTypeBuilder<MechanicalJobcard> mechanicalJobcardConfig)
    {
        mechanicalJobcardConfig.HasOne(j => j.Vehicle).WithOne(v => v.MechanicalJobcard).HasForeignKey<Jobcard>(j => j.VehicleId);
    }
}

但是我在以下错误Add-Migration：

You are configuring a relationship between 'PanelBeatingJobcard' and 'Vehicle' but have specified a foreign key on 'Jobcard'. The foreign key must be defined on a type that is part of the relationship

如果我同时删除这两种配置，则会收到以下错误消息Add-Migration：

Both relationships between 'Jobcard.Vehicle' and 'Vehicle' and between 'MechanicalJobcard' and 'Vehicle.MechanicalJobcard' could use {'VehicleId'} as the foreign key. To resolve this configure the foreign key properties explicitly on at least one of the relationships.

编辑：

如果将注释中建议的“实体类型配置”更改为以下内容：

class PanelBeatingJobCardEntityTypeConfiguration: IEntityTypeConfiguration<PanelBeatingJobcard>
{
    public void Configure(EntityTypeBuilder<PanelBeatingJobcard> panelBeatinglJobcardConfig)
    {
        panelBeatinglJobcardConfig.HasOne(j => j.Vehicle).WithOne(v => v.PanelBeatingJobcard).HasForeignKey<PanelBeatingJobcard>(j => j.VehicleId);
    }
}
class MechanicalJobcardEntityTypeConfiguration: IEntityTypeConfiguration<MechanicalJobcard>
{
    public void Configure(EntityTypeBuilder<MechanicalJobcard> mechanicalJobcardConfig)
    {
        mechanicalJobcardConfig.HasOne(j => j.Vehicle).WithOne(v => v.MechanicalJobcard).HasForeignKey<MechanicalJobcard>(j => j.VehicleId);
    }
}

我在Migrations文件中得到重复的VehicleId键（VehicleId和VehicleId1）：

 table.ForeignKey(
    name: "FK_jobcard_vehicles_VehicleId",
    column: x => x.VehicleId,
    principalSchema: "dbo",
    principalTable: "vehicles",
    principalColumn: "VehicleId",
    onDelete: ReferentialAction.Cascade);
table.ForeignKey(
    name: "FK_jobcard_vehicles_VehicleId1",
    column: x => x.VehicleId,
    principalSchema: "dbo",
    principalTable: "vehicles",
    principalColumn: "VehicleId",
    onDelete: ReferentialAction.Cascade);

托德·斯凯尔顿

我创建了一个完整的工作示例，该示例在创建初始迁移时没有任何问题。它们映射到相同的表并使用相同的外键。

添加HasBaseType可能是问题所在。这将指示EF这两个实体共享基本类型。

class Program
{
    static void Main()
    {

    }

    public class Vehicle
    {
        public int Id { get; set; }
        public PanelBeatingJobcard PanelBeatingJobcard { get; set; }
        public MechanicalJobcard MechanicalJobcard { get; set; }
    }

    public abstract class Jobcard
    {
        public int Id { get; set; }
        public int VehicleId { get; set; }
        public Vehicle Vehicle { get; set; }
    }

    public class PanelBeatingJobcard : Jobcard { }

    public class MechanicalJobcard : Jobcard { }

    public class Context: DbContext
    {
        protected override void OnConfiguring(DbContextOptionsBuilder optionsBuilder)
        {
            optionsBuilder.UseSqlServer();
        }

        protected override void OnModelCreating(ModelBuilder modelBuilder)
        {
            modelBuilder.Entity<MechanicalJobcard>(buildAction =>
            {
                buildAction.HasBaseType<Jobcard>();
                buildAction.HasOne(e => e.Vehicle).WithOne(e => e.MechanicalJobcard).HasForeignKey<MechanicalJobcard>(e => e.VehicleId);
            });

            modelBuilder.Entity<PanelBeatingJobcard>(buildAction =>
            {
                buildAction.HasBaseType<Jobcard>();
                buildAction.HasOne(e => e.Vehicle).WithOne(e => e.PanelBeatingJobcard).HasForeignKey<PanelBeatingJobcard>(e => e.VehicleId);
            });
        }
    }
}

迁移输出

public partial class InitialMigration : Migration
{
    protected override void Up(MigrationBuilder migrationBuilder)
    {
        migrationBuilder.CreateTable(
            name: "Vehicle",
            columns: table => new
            {
                Id = table.Column<int>(type: "int", nullable: false)
                    .Annotation("SqlServer:Identity", "1, 1")
            },
            constraints: table =>
            {
                table.PrimaryKey("PK_Vehicle", x => x.Id);
            });

        migrationBuilder.CreateTable(
            name: "Jobcard",
            columns: table => new
            {
                Id = table.Column<int>(type: "int", nullable: false)
                    .Annotation("SqlServer:Identity", "1, 1"),
                VehicleId = table.Column<int>(type: "int", nullable: false),
                Discriminator = table.Column<string>(type: "nvarchar(max)", nullable: false)
            },
            constraints: table =>
            {
                table.PrimaryKey("PK_Jobcard", x => x.Id);
                table.ForeignKey(
                    name: "FK_Jobcard_Vehicle_VehicleId",
                    column: x => x.VehicleId,
                    principalTable: "Vehicle",
                    principalColumn: "Id",
                    onDelete: ReferentialAction.Cascade);
            });

        migrationBuilder.CreateIndex(
            name: "IX_Jobcard_VehicleId",
            table: "Jobcard",
            column: "VehicleId",
            unique: true);
    }

    protected override void Down(MigrationBuilder migrationBuilder)
    {
        migrationBuilder.DropTable(
            name: "Jobcard");

        migrationBuilder.DropTable(
            name: "Vehicle");
    }
}

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