c# - Entity Framework - 代码优先 - 数据注释 - 不必要的外键列

Question

Entity Framework 在我的 AccountCompanyRole 表中创建了两个不必要的列。

账户公司

public class AccountCompany
{
    [Key, Column(Order = 0), ForeignKey("Account")]
    public int AccountID { get; set; }

    [Key, Column(Order = 1), ForeignKey("Company")]
    public int CompanyID { get; set; }

    public virtual Account Account { get; set; }

    public virtual Company Company { get; set; }

    public virtual ICollection<AccountCompanyRole> AccountCompanyRoles { get; set; }
}

AccountCompanyRoles

public class AccountCompanyRole
{
    [Key, Column(Order = 0), ForeignKey("AccountCompany")]
    public int AccountID { get; set; }

    [Key, Column(Order = 1), ForeignKey("AccountCompany")]
    public int CompanyID { get; set; }

    [Key, Column(Order = 2), ForeignKey("Role")]
    public int RoleID { get; set; }

    public virtual AccountCompany AccountCompany { get; set; }

    public virtual Role Role { get; set; }
}

OnModelCreating

    protected override void OnModelCreating(DbModelBuilder modelBuilder)
    {
        modelBuilder.Entity<AccountCompanyRole>()
            .HasRequired(p => p.AccountCompany)
            .WithMany()
            .WillCascadeOnDelete(false);

        base.OnModelCreating(modelBuilder);
    }

数据库中的结果

如您所见，EF 在 AccountCompanyRoles 中添加了两个额外的外键，即使我在数据注释中指定了主键和外键。

问题

1. 如何阻止它创建 AccountCompany_AccountID 和 AccountCompany_CompanyID？

2. 这是我想要的最佳结构吗？我是否应该改用一个主键并将 IsUnique 索引放在 AccountID 和 CompanyID 上？这可能会解决我的问题..

Answer 1

How do I prevent it from creating AccountCompany_AccountID and AccountCompany_CompanyID?

首先，从 CompanyID 和 RoleID 中删除 ForeignKey 属性。

然后将 ForeignKey 属性放在您的 AccountCompany 成员上，如下所示:

public class AccountCompanyRole
{
    [Key, Column(Order = 0)]
    public int AccountID { get; set; }

    [Key, Column(Order = 1)]
    public int CompanyID { get; set; }

    [Key, Column(Order = 2), ForeignKey("Role")]
    public int RoleID { get; set; }

    [ForeignKey("AccountID, CompanyID")]
    public virtual AccountCompany AccountCompany { get; set; }

    public virtual Role Role { get; set; }
}

或者像这样使用流畅的配置:

modelBuilder.Entity<AccountCompanyRole>()
            .HasRequired(r => r.AccountCompany)
            .WithMany(c => c.AccountCompanyRoles)
            .HasForeignKey(r => new { r.AccountID, r.CompanyID })
            .WillCascadeOnDelete(false);

Is this the best structure for what I am after? Should I instead use one primarykey and put IsUnique index on AccountID and CompanyID? This would probably solve my problem..

IMO 两者都是有效的方法，请使用更适合您需求的方法。