Question

我有一个现有的数据库，其PK是一个数字（18,0），一个FK是一个int。当我尝试使用导航属性时，EF会抛出一个无效的强制转换异常。

有没有办法映射这种关系，以解决无效的演员？

在下面的代码中，promo_cfg.pc_id是数字（18,0），promo.pc_id是int。

public class PromotionMap : EntityTypeConfiguration<Promotion>
{
    public PromotionMap()
    {
        // Primary Key
        this.HasKey(p => p.PromotionId);

        // Properties

        // table and column mappings
        this.ToTable("promo");
        this.Property(p => p.PromotionId).HasColumnName("p_id");
        this.Property(p => p.PromotionConfigId).HasColumnName("pc_id");
        this.Property(p => p.PromotionCode).HasColumnName("p_code");


        this.HasRequired(t => t.PromotionConfig) 
            .WithMany(t => t.Promotions)
            .HasForeignKey(d => new { d.PromotionConfigId }); 
    }
}

public class Promotion
{
    public decimal PromotionId { get; set; }
    public int PromotionConfigId { get; set; }
    public string PromotionCode { get; set; }
}

public PromotionConfigMap()
{
    // Primary Key
    this.HasKey(s => s.PromotionConfigId);

    // Properties
    // Table and Column mappings
    this.ToTable("promo_cfg");

    this.Property(p => p.PromotionConfigId).HasColumnName("pc_id");
    this.Property(p => p.AllowOrders).HasColumnName("allow_orders");
    this.HasOptional(p => p.Promotions).WithRequired().Map(x => x.MapKey("pc_id"));
}

public class PromotionConfig
{
    public int PromotionConfigId { get; set; }
    public int AllowOrders { get; set; }
    public virtual ICollection<Promotion> Promotions { get; set; }
}

Answer 1

可能是一个大的MAY，有一个非物化的FK：

HasOptional(x => x.SomeProperty).WithMany().Map(x => x.MapKey("intDbColumnName"));

=============================================== =========

我删除了所有不需要的代码，以下内容应该：

public class Promotion
{
    public decimal PromotionId { get; set; }
    //Here you do not materialize the FK
    public PromotionConfig PromotionConfig { get; set; }
}

public class PromotionConfig
{
    public decimal PromotionConfigId { get; set; } // you can't do otherwise as
                                                   //you must declare a PK for EF
    public virtual ICollection<Promotion> Promotions { get; set; }
}


public class PromotionMap : EntityTypeConfiguration<Promotion>
{
    public PromotionMap()
    {
        // Primary Key
        this.HasKey(p => p.PromotionId);

        // Properties

        // table and column mappings
        this.ToTable("promo");
        this.Property(p => p.PromotionId).HasColumnName("p_id");

        //if I well understand pc_id is an int that relates to a decimal
        this.HasRequired(p => p.PromotionConfig) 
            .WithMany(pc => pc.Promotions)
            .Map(p => p.MapKey("pc_id")); 

    }
}


public class PromotionConfigMap : EntityTypeConfiguration<PromotionConfig> {

    public PromotionConfigMap()
    {
        // Primary Key
        this.HasKey(s => s.PromotionConfigId);

        // Properties
        // Table and Column mappings
        this.ToTable("promo_cfg");
    }

}

实体框架6 - 导航属性PK和FK是不同的类型

1 个答案: