Question

我在MVC项目中有两个以下两个模型：

using System.Collections.Generic;
using System.ComponentModel.DataAnnotations;
using System.ComponentModel.DataAnnotations.Schema;

namespace RiskDotNet.Models
{
    public class Customer
    {
        [Key, Column(Order = 0)]
        public string SrcSys { get; set; }
        [Key, Column(Order = 1)]
        public string CustId { get; set; }
        public string CustNm { get; set; }

        public virtual ICollection<Account> Accounts { get; set; }
    }
}

和

using System.Collections.Generic;
using System.ComponentModel.DataAnnotations;
using System.ComponentModel.DataAnnotations.Schema;

namespace RiskDotNet.Models
{
    public class Account
    {
        [Key, Column(Order = 0)]
        [ForeignKey("Customer"), Column(Order = 0)]
        public string SrcSys { get; set; }
        [Key, Column(Order = 1)]
        [ForeignKey("Customer"), Column(Order = 1)]
        public string CustId { get; set; }
        [Key, Column(Order = 2)]
        public string AccId { get; set; }
        public string BrId { get; set; }
        public string ProdId { get; set; }

        public virtual ICollection<Balance> Balances { get; set; }
        public virtual Customer Customers { get; set; }
    }
}

Customer可由复合密钥源系统（SrcSys）＆amp;客户ID（CustId）。虽然可以通过源系统（Account），客户ID（SrcSys）以及帐户ID（CustId）识别AccId。但第二个模型不允许我使用另一个专栏。

请查看您是否有专家可以提供帮助。

提前完成。

Answer 1

通过使用流畅的API配置，我发现指定复合键（PK和FK）更容易理解，并且更不容易出错：

modelBuilder.Entity<Account>()
    .HasRequired(e => e.Customers) // the property should really be called Customer, currently it sounds like collection
    .WithMany(e => e.Accounts)
    .HasForeignKey(e => new { e.SrcSys, e.CustId }); // <= the composite FK

但如果您更喜欢数据注释，只需在导航属性上应用ForeignKey属性，并提供带有FK属性名称的逗号分隔列表：

public class Account
{
    [Key, Column(Order = 0)]
    public string SrcSys { get; set; }
    [Key, Column(Order = 1)]
    public string CustId { get; set; }
    [Key, Column(Order = 2)]
    public string AccId { get; set; }
    public string BrId { get; set; }
    public string ProdId { get; set; }

    public virtual ICollection<Balance> Balances { get; set; }

    [ForeignKey("SrcSys,CustId")] // <= the composite FK
    public virtual Customer Customers { get; set; }
}

复合外键是复合主键

1 个答案: