7

我有这个模型

public class State
{
    public State()
    {
        this.Promotions = new List<Promotion>();
        this.Branches = new List<Branch>();
        this.Stores = new List<Store>();
    }

    public int Id { get; set; }
    public string Description { get; set; }

    public virtual ICollection<Promotion> Promotions { get; set; }
    public virtual ICollection<Store> Stores { get; set; }
    public virtual ICollection<Branch> Branches { get; set; }
}

public class Store
{
    public Store()
    {
        this.Promotions = new List<Promotion>();
        this.Branches = new List<Branch>();
    }

    public int Id { get; set; }
    public string Name { get; set; }

    public virtual ICollection<Promotion> Promotions { get; set; }
    public virtual ICollection<Branch> Branches { get; set; }

    public int StateId { get; set; } // Foreign key
    public virtual State State { get; set; } // Navigation Property
}

public class Branch
{
    public Branch()
    {
        this.Promotions = new List<Promotion>();
    }

    public int Id { get; set; }
    public string Name { get; set; }
    public int StoreId { get; set; } // Foreign key
    public int StateId { get; set; } // Foreign key

    public virtual Store Store { get; set; } // Navigation Property
    public virtual State State { get; set; } // Navigation Property

    public virtual ICollection<Promotion> Promotions { get; set; }
}

    public class Promotion
{
    public Promotion()
    {
        this.Stores = new List<Store>();
        this.Branches = new List<Branch>();
        this.Productos = new List<Producto>();
    }

    public int Id { get; set; }
    public string Name { get; set; }
    public int StateId { get; set; }

    public virtual ICollection<Store> Stores { get; set; }
    public virtual ICollection<Branch> Branches { get; set; }
    public virtual ICollection<Product> Products { get; set; }

    public virtual State State { get; set; }

}

这在我的上下文中：

// State
modelBuilder.Entity<State>()
    .HasMany(p => p.Promotions)
    .WithRequired(e => e.State)
    .WillCascadeOnDelete(false);

modelBuilder.Entity<State>()
    .HasMany(s => s.Branches)
    .WithRequired(e => e.State)
    .WillCascadeOnDelete(false);

modelBuilder.Entity<State>()
   .HasMany(e => e.Stores)
   .WithRequired(e => e.State)
   .WillCascadeOnDelete(true);

 // Store
modelBuilder.Entity<Store>()
    .HasMany(b => b.Branches)
    .WithRequired(s => s.Store)
    .WillCascadeOnDelete(true);

// Many to many
modelBuilder.Entity<Store>().
  HasMany(p => p.Promotions).
  WithMany(s => s.Stores).
  Map(
   m =>
   {
       m.MapLeftKey("StoreId");
       m.MapRightKey("PromotionId");
       m.ToTable("Store_Promotion");
   });

modelBuilder.Entity<Promotion>().
 HasMany(e => e.Products).
 WithMany(p => p.Promotiones).
 Map(
  m =>
  {
      m.MapLeftKey("PromotionId");
      m.MapRightKey("ProductoId");
      m.ToTable("Promotion_Producto");
  });

modelBuilder.Entity<Branch>().
 HasMany(p => p.Promotiones).
 WithMany(b => b.Branches).
 Map(
  m =>
  {
      m.MapLeftKey("BranchId");
      m.MapRightKey("PromotionId");
      m.ToTable("Branch_Promotion");
  });

现在，如果我打开多个状态的 WillCascadeOnDelete （流畅映射中的前三个），我会收到错误

测试方法 Proj.Data.Tests.UnitTest1.TestPromotion 抛出异常：
System.Data.SqlClient.SqlException：在表 'Branch' 上引入 FOREIGN KEY 约束 'FK_dbo.Branch_dbo.Store_StoreId' 可能会导致循环或多个级联路径。指定 ON DELETE NO ACTION 或 ON UPDATE NO ACTION，或修改其他 FOREIGN KEY 约束。无法创建约束。请参阅以前的错误。

我知道，我读过 Julie Lerman 的书：

某些数据库（包括 SQL Server）不支持指定级联删除指向同一个表的多个关系

由于多对多关系表具有来自两个相关表的级联删除，因此发生这种情况。

所以，我的问题是：这里唯一的选择是关闭父表上的级联删除并手动处理关系表上的删除？Entity Framework 5 对此没有任何解决方法吗？

4

1 回答 1

6

好的，我明白了这个问题。不是多对多关系，问题是这个

State -> Promotion -> PromotionStore
State -> Branch -> BranchPromotion
State -> Store -> StorePromotion

然后 Store、Branch 和 Store 对 State 有 FK。因此，如果我删除 State PromotionStore 可以通过第一种和第三种可能性到达。

我最终做的是关闭 State 的级联删除并手动删除相关记录，如下所示：

public override void Delete(State state)
{
   DbContext.Entry(state).Collection(x => x.Promotions).Load();
   DbContext.Entry(state).Collection(x => x.Stores).Load();
   DbContext.Entry(state).Collection(x => x.Branches).Load();

   var associatedPromotions = state.Promotions.Where(p => p.StateId == state.Id);
   associatedPromotions.ToList().ForEach(r => DbContext.Set<Promotion>().Remove(r));

   var associatedStores = state.Stores.Where(e => e.StateId == state.Id);
   associatedStores.ToList().ForEach(e => DbContext.Set<Store>().Remove(e));

   var associatedBranches = state.Branches.Where(s => s.StateId == state.Id);
   associatedBranches.ToList().ForEach(s => DbContext.Set<Branch>().Remove(s));

   base.Delete(state);
}
于 2012-11-19T15:47:31.070 回答