EF 6 - 代码首次无效的一对一外键关系

Question

设计背景 ：

我正在尝试为以下数据库结构创建代码优先的EF6映射：

数据库设计如下：我们有一个CustomerRelationship表，其中包含CustomerID，然后是“RelatedID”，而不是将“CustomerID”作为所有相关实体（就业，费用，收入等）的外键。 “列将包含相关实体的密钥。 例如，假设我为CustomerID = 1添加了一份就业记录，那么将发生以下情况：

1. 在CustomerRelationship中创建记录，设置CustomerID = 1 RelatedID = {new autogenerated EmploymentID，假设5} CustomerRelationshipTypeID = 55（查找表中的Id表明此记录属于就业类型）

2. 在就业表中创建记录（EmploymentID = 5）

上述结构适用于与客户关联的所有实体。

我有为就业工作的关系映射，这是我的课程：

public abstract class EntityBase : IEntity
{
    #region IEntity Members
    public int Id { get; set; }

    public DateTime CreatedDate { get; set; }

    public int CreatedUserId { get; set; }

    public int CreatedSource { get; set; }

    public DateTime ModifiedDate { get; set; }

    public int ModifiedUserId { get; set; }

    public int? DataMigrationId { get; set; } 

    public bool IsActive { get; set; }                                    
    #endregion
}


public class Employment : EntityBase
{
    // ... all properties here.. removed most so easier to read
    public int EmploymentTypeId { get; set; }    

    **public virtual ICollection<EmploymentRelationship> EmploymentRelationships { get; set; }**
}

    public EmploymentMap()
    {
        this.HasKey(t => t.Id);
        ToTable("tblEmployment");
        Property(t => t.Id).HasColumnName("EmploymentID");    
        // Mapping for all properties follow       
    }

public abstract partial class CustomerRelationship : EntityBase
{
    public int CustomerId { get; set; }

    public decimal? PercentageShare { get; set; }

    public int CustomerRelationshipTypeId { get; set; }

    public int RelatedId { get; set; }
}

public class EmploymentRelationship : CustomerRelationship
{       
    public virtual Employment Employment { get; set; }
}

    public EmploymentRelationshipMap()
    {
        this.HasKey(t => t.Id);

        Map<EmploymentRelationship>(m =>
        {
            m.Requires("CustomerRelationshipTypeID").HasValue(55).IsRequired(); // Define lookup value for type of employment
            m.ToTable("tblCustomerRelationship");
        });

        Property(t => t.Id).HasColumnName("CustomerRelationshipID");
        Property(t => t.CustomerId).HasColumnName("CustomerID");
        Property(t => t.RelatedId).HasColumnName("RelatedID");

        HasRequired(t => t.Employment)
            .WithMany(t => t.EmploymentRelationships)
            .HasForeignKey(t => t.RelatedId);
    }

public class Customer : EntityBase
{
    // Customer Properties...
    public Customer()
    {
        EmploymentRelationships = new List<EmploymentRelationship>();
    }

    public virtual ICollection<EmploymentRelationship> EmploymentRelationships { get; set; }
}

    public CustomerMap()
    {
        this.HasKey(t => t.Id);

        ToTable("tblCustomer");

        Property(t => t.Id).HasColumnName("CustomerID");
    }


public class CustomerContext 
{
    public CustomerContext()
        : base(SymmetryCopy.context_connectionstring_main)
    {
    }

    public virtual DbSet<Customer> Customers { get; set; }
    public virtual DbSet<Employment> Employments { get; set; }

    #region Customer Relationship entity mappings
    public virtual DbSet<EmploymentRelationship> EmploymentRelationships { get; set; }
    #endregion

    protected override void OnModelCreating(DbModelBuilder modelBuilder)
    {
        modelBuilder.Configurations.Add(new CustomerMap());
        modelBuilder.Configurations.Add(new EmploymentMap());

        #region Customer Relationship entity mappings
        modelBuilder.Configurations.Add(new EmploymentRelationshipMap());
        #endregion
    }
}

CustomerRepo查询上下文并返回结果：

public class CustomerRepository : BaseRepository<Customer, CustomerContext>, ICustomerRepository
{
    public CustomerRepository() : 
        base(new CustomerContext())
    {

    }

    public async Task<List<Employment>> GetEmployments(int customerId)
    {
        List<Employment> employments = new List<Employment>();
        using (var context = new CustomerContext())
        {
            var employmentRelationships = context.EmploymentRelationships.Where(l => l.CustomerId == customerId).ToList();
            employments = employmentRelationships.Select(x => x.Employment).ToList();
        }
        return employments;
    }
}

然后，上述方法GetEmployments将返回与CustomerID匹配的所有记录，其中CustomerRelationshipTypeID = 55（Employments的键值）。 见下面的回报。

现在来看看我的实际问题：

当我尝试连接另一个实体类型，即：Expense时，遵循与Employment相同的方法，创建Expense.cs，ExpenseMap.cs，ExpenseRelationship.cs，ExpenseRelationshipMap.cs，在ExpenseRElationshipMap.cs中具有以下内容：

public class ExpenseRelationshipMap
{
    public ExpenseRelationshipMap()
    {
        HasKey(t => t.Id);

        Map<ExpenseRelationship>(m =>
        {
            m.Requires("CustomerRelationshipTypeID").HasValue(60).IsRequired();
            m.ToTable("tblCustomerRelationship");  // Define lookup value for type of Expense
        });

        Property(t => t.Id).HasColumnName("CustomerRelationshipID");
        Property(t => t.CustomerId).HasColumnName("CustomerID");
        Property(t => t.RelatedId).HasColumnName("RelatedID");
        Property(t => t.PercentageShare).HasColumnName("PercentageShare");

        HasRequired(t => t.Expense)
            .WithMany(t => t.ExpenseRelationships)
            .HasForeignKey(t => t.RelatedId);
    }
}

一旦我创建了Map条目，如上所示，在查询GetEmployments（）方法时，我现在得到以下异常：

“实体类型'ExpenseRelationship'和'EmploymentRelationship'不能共享表'tblCustomerRelationship'，因为它们不在同一类型层次结构中，或者没有有效的一对一外键关系，它们之间具有匹配的主键。”，

我错过了什么？

UPDATE

根据jjj的评论，我更新了我的映射并创建了一个CustomerRelationship.cs基类。

public class Employment : EntityBase
{      
    public string EmployerName { get; set; }

    public string EmployerContactFirstName { get; set; }

    public string EmployerContactSurname { get; set; }

    public virtual ICollection<EmploymentRelationship> EmploymentRelationships { get; set; }
}

public class Expense : EntityBase
{
    public string Description { get; set; }

    public virtual ICollection<ExpenseRelationship> ExpenseRelationships { get; set; }
}

public abstract class CustomerRelationship : EntityBase
{
    public int CustomerId { get; set; }

    public int? CustomerRelationshipTypeId { get; set; }

    public int RelatedId { get; set; }
}

public class EmploymentRelationship : CustomerRelationship
{
    public virtual Employment Employment { get; set; }
}

public class ExpenseRelationship: CustomerRelationship
{
    public virtual Expense Expense{ get; set; }
}

public class CustomerRelationshipMap : BaseMap<CustomerRelationship>
{
    public CustomerRelationshipMap()
    {
        ToTable("CustomerRelationship");

        Map<EmploymentRelationship>(m => m.Requires("CustomerRelationshipTypeID").HasValue(55));
        Map<ExpenseRelationship>(m => m.Requires("CustomerRelationshipTypeID").HasValue(60));

        Property(t => t.Id).HasColumnName("CustomerRelationshipID");            
        Property(t => t.CustomerId).HasColumnName("CustomerID");
        Property(t => t.RelatedId).HasColumnName("RelatedID");            
    }

public class EmploymentRelationshipMap : BaseMap<EmploymentRelationship>
{
    public EmploymentRelationshipMap()
    {
        HasRequired(t => t.Employment)
            .WithMany(t => t.EmploymentRelationships)
            .HasForeignKey(t => t.RelatedId);
    }
}

public class ExpenseRelationshipMap : BaseMap<ExpenseRelationship>
{
    public ExpenseRelationshipMap()
    {
        HasRequired(t => t.Expense)
            .WithMany(t => t.ExpenseRelationships)
            .HasForeignKey(t => t.RelatedId);
    }
}

public class CustomerContext : BaseContext
{
    public CustomerContext()
        : base(context_connectionstring_main)
    {
    }

    public virtual DbSet<Customer> Customers { get; set; }
    public virtual DbSet<Employment> Employments { get; set; }

    public virtual DbSet<CustomerRelationship> CustomerRelationships { get; set; }
    public virtual DbSet<EmploymentRelationship> EmploymentRelationships { get; set; }
    public virtual DbSet<ExpenseRelationship> ExpenseRelationships { get; set; }

    protected override void OnModelCreating(DbModelBuilder modelBuilder)
    {
        modelBuilder.Configurations.Add(new CustomerMap());
        modelBuilder.Configurations.Add(new EmploymentMap());

        modelBuilder.Configurations.Add(new CustomerRelationshipMap());
        modelBuilder.Configurations.Add(new EmploymentRelationshipMap());
        modelBuilder.Configurations.Add(new ExpenseRelationshipMap());
    }
}

当我像这样查询客户上下文时：

var relationships = context.CustomerRelationships.Where(l => l.CustomerId == customerId).ToList();

我得到以下异常：

“外键组件'RelatedId'不是'EmploymentRelationship'类型的声明属性。验证它是否未从模型中明确排除，并且它是有效的原始属性。”，

Answer 1

您需要所有共享属性（包括主键）的基类配置。

public class CustomerRelationshipMap : EntityTypeConfiguration<CustomerRelationship>
{
    public CustomerRelationshipMap()
    {
        ToTable("tblCustomerRelationship");

        Map<EmploymentRelationship>(m => m.Requires("CustomerRelationshipTypeID").HasValue(55));
        Map<ExpenseRelationship>(m => m.Requires("CustomerRelationshipTypeID").HasValue(60));

        HasKey(t => t.Id);
        Property(t => t.Id).HasColumnName("CustomerRelationshipID");
        Property(t => t.CustomerId).HasColumnName("CustomerID");
        Property(t => t.RelatedId).HasColumnName("RelatedID");
    }
}

然后，您应该能够在其他配置类中使用派生类特定的配置（但是，这不是我之前尝试过的）。

编辑

此外，对于使用相同基类属性的派生类，不能具有不同的外键关联。 我能想到几个选项，但这取决于你的情况：

1. 单独的外键之间的关联EmploymentRelationship - Employment和ExpenseRelationship - Expense 。
2. 给Employment和Expense一个共同的基础 - 虽然这可能会破坏你想要做的目的......
3. 独立1：0..1之间的关系CustomerRelationship和Employment / Expense （和摆脱EmploymentRelationship和ExpenseRelationship ）
4. Employment和Expense继承自CustomerRelationship （并摆脱EmploymentRelationship和ExpenseRelationship ）的TPT继承

来源

• 关于EF Code First Fluent API，TPH和外键的难度
• 如何在TPH TPT对象之间映射外键 - 实体框架代码优先