Question

鉴于以下粗略的代码优先架构，目标看起来非常简单。 Invoice可以来自Company，也可以Invoices，public class Company { public int Id { get; set; } public virtual ICollection<Invoice> Invoices { get; set; } } public class Invoice { public int Id { get; set; } public int FromCompanyId { get; set; } public int ToCompanyId { get; set; } public virtual Company FromCompany { get; set; } public virtual Company ToCompany { get; set; } }集合应该包含所有发票，无论它是什么。

Company_Id

您会在迁移中注意到，出于显而易见的原因生成了第三个Invoices以支持Invoices导航属性，因为仅 以支持1 Nav Prop - ＆GT; 1 FK安排。

我的问题是，是否可以让IC<Inv> InvoicesFrom属性包含两者，或者我是否应该单独映射它们（即IC<Inv> InvoicesTo，InverseProperty）并创建客户端 - 手动收集。

我试过了：

在FromCompany和ToCompany上使用[ForeignKey(nameof(FromCompanyId)), InverseProperty(nameof(Company.Invoices))] public virtual Company FromCompany { get; set; } [ForeignKey(nameof(ToCompanyId)), InverseProperty(nameof(Company.Invoices))] public virtual Company ToCompany { get; set; }会混淆EF，因为它无法确定关系的主要结束。

modelBuilder.Entity<Company>() .HasMany(m => m.Invoices) .WithRequired(m => m.ToCompany) .WillCascadeOnDelete(false); modelBuilder.Entity<Company>() .HasMany(m => m.Invoices) .WithRequired(m => m.FromCompany) .WillCascadeOnDelete(false);

使用流畅的API来映射它们，但它只考虑从代码角度来看的第二个。

{{1}}

如果不可能的话，当然没有重大问题，我可以发誓我以前做过。

Answer 1

对于后代，这里是一个完整版本的变通方法，用于维护包含两个集合在一起的公司的IEnumerable<Invoices>。

public class MyContext : DbContext
{
    public MyContext() : base("DefaultConnection") { }
    protected override void OnModelCreating(DbModelBuilder modelBuilder)
    {
        base.OnModelCreating(modelBuilder);

        modelBuilder.Entity<Company>().HasMany(c => c.InvoicesFrom).WithRequired(i => i.FromCompany).WillCascadeOnDelete(false);
        modelBuilder.Entity<Company>().HasMany(c => c.InvoicesTo).WithRequired(i => i.ToCompany).WillCascadeOnDelete(false);
    }

    public DbSet<Company> Companies { get; set; }
    public DbSet<Invoice> Invoices { get; set; }
}

public class Company
{
    public int Id { get; set; }
    public virtual ICollection<Invoice> InvoicesFrom { get; set; }
    public virtual ICollection<Invoice> InvoicesTo { get; set; }

    [NotMapped]
    public IEnumerable<Invoice> Invoices
    {
        get {
            return InvoicesFrom.Union(InvoicesTo);
        }
    }
}

public class Invoice
{
    public int Id { get; set; }
    public int FromCompanyId { get; set; }
    public int ToCompanyId { get; set; }
    public virtual Company FromCompany { get; set; }
    public virtual Company ToCompany { get; set; }
}

2个外键，1个导航属性可以通过两个

1 个答案: