EF核心映射一个对象的一个​​字段到另一个对象的两个不同字段

Question

我有一个货币对象和一个产品对象。我需要将货币与产品对象的批发货币以及零售场链接起来，

public class Currency
    {
        /// <summary>
        /// Id is the 3 character ISO currency code
        /// </summary>
        [StringLength(3)]
        public string Id { get; set; }

        [StringLength(100)]
        public string Name { get; set; }
    }

我有另一个带有2个货币字段的对象：

public class Product
    {
        public int Id { get; set; }

        public decimal WholesaleRate { get; set; }
        public string WholesaleCurrencyId { get; set; }
        public virtual Currency WholesaleCurrency { get; set; }

        public decimal RetailRate { get; set; }
        public string RetailCurrencyId { get; set; }
        public virtual Currency RetailCurrency { get; set; }
    }

我的查询是：

1. 这两个对象之间有什么关系？一对多还是一对一？
2. 我如何表达这些关系？上述正确吗？

Answer 1

您可以尝试以下演示：

以货币：

public class Currency
 {
        /// <summary>
        /// Id is the 3 character ISO currency code
        /// </summary>
        [StringLength(3)]
        public string Id { get; set; }

        [StringLength(100)]
        public string Name { get; set; }

        public virtual ICollection<Product> ProductWholesale { get; set; }
        public virtual ICollection<Product> ProductRetail { get; set; }
    }

中的货币：

public class Product
    {
        public int Id { get; set; }

        public decimal WholesaleRate { get; set; }
        public string WholesaleCurrencyId { get; set; }
        public virtual Currency WholesaleCurrency { get; set; }

        public decimal RetailRate { get; set; }
        public string RetailCurrencyId { get; set; }
        public virtual Currency RetailCurrency { get; set; }
    }

在您的上下文中添加下面的代码：

 protected override void OnModelCreating(ModelBuilder modelBuilder)
        {
            modelBuilder.Entity<Product>()
                .HasOne(p => p.WholesaleCurrency)
                .WithMany(t => t.ProductWholesale)
                .HasForeignKey(m => m.WholesaleCurrencyId )
                .OnDelete(DeleteBehavior.Restrict);

            modelBuilder.Entity<Product>()
                .HasOne(p => p.RetailCurrency)
                .WithMany(t => t.ProductRetail)
                .HasForeignKey(m => m.RetailCurrencyId)
                .OnDelete(DeleteBehavior.Restrict);
        }