c# - 与 TPT 代码优先 Entity Framework 中的引用约束冲突

Question

我在 Entity Framework 6 中使用 TPT 代码优先并具有以下设置:

public abstract class Product
{
    [Key]
    public string ProductID { get; set; }
    // a bunch of trivial properties like dates and floats
}

[Table("SpecialProducts")]
public class SpecialProduct : Product
{
    // more trivial properties
    public List<Property> MyProperties { get; set; }
}

public class Property
{
    [Key]
    public int ID { get; set; }
    [Required]
    public SpecialProduct Product { get; set; }
    // property data
}

public class MyDbContext : DbContext
{
    public DbSet<Product> AllProducts { get; set; }

    public MyDbContext()
        : base("MyDataBase")
    {}

    public RemoveSomeProducts()
    {
        var products = from product in AllProducts where /* some condition */ select product;
        AllProducts.RemoveRange(products);
        SaveChanges();
    }

    protected override void OnModelCreating(DbModelBuilder modelBuilder)
    {
        // I know I don't need both statements, and my guess is I need the first, but at this point I don't know anything anymore
        modelBuilder.Entity<Property>()
            .HasRequired(property => property.Product)
            .WithMany(product => product.MyProperties)
            .WillCascadeOnDelete(true);

        modelBuilder.Entity<SpecialProduct>()
            .HasMany(product => product.MyProperties)
            .WithRequired(property => property.Product)
            .WillCascadeOnDelete(true);
    }

}

调用 RemoveSomeProducts() 时出现以下异常:

SqlException: The DELETE statement conflicted with the REFERENCE constraint "FK_dbo.Properties_dbo.SpecialProducts_Product_ProductID". The conflict occurred in database "MyDataBase", table "dbo.Properties", column 'Product_ProductID'.

对我来说，这听起来像是属于已删除 SpecialProducts 的 Properties 没有被删除。我对数据库没有什么经验，但根据我的理解，这应该使用级联删除来修复，但我似乎无法配置它。

所以我的问题显然是:我该如何解决这个问题？

对我的情况似乎没有帮助但可能对其他人有用的潜在重复项:

EF6 Cascade Delete

Code First Cascade Delete

TPT Cascade Delete

Answer 1

首先，您必须在查询中明确包含您的导航属性。由于某些原因，RemoveRange 无法按预期使用级联删除，但如果您逐个迭代并删除它，它就可以工作。

var products = Set<SpecialProduct>().Include(p => p.MyProperties).ToList();
products.ForEach(p => AllProducts.Remove(p));
SaveChanges();