我正在创建一个 ASP.Net MVC 3 应用程序,并且在尝试使用迁移更新我的数据库时遇到了外键约束问题。我正在使用 Code-First,我得到的错误是:
在表“CategoryItemValues”上引入 FOREIGN KEY 约束“FK_CategoryItemValues_CategoryProperties_CategoryPropertyId”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。
这是我的课程:
public class Category
{
public int Id { get; set; }
[Display(Name = "Category Name")]
public string CategoryName { get; set; }
[Display(Name = "Display Name")]
public string DisplayName { get; set; }
[Display(Name = "Display Order")]
public int DisplayOrder { get; set; }
public bool IsTab { get; set; }
public bool Active { get; set; }
public virtual List<CategoryProperty> Properties { get; set; }
}
public class CategoryProperty
{
public int Id { get; set; }
public int CategoryId { get; set; }
[Display(Name="Property Name")]
public string PropertyName { get; set; }
[Display(Name = "Display Order")]
public int DisplayOrder { get; set; }
public virtual Category Category { get; set; }
}
public class CategoryItem
{
public int Id { get; set; }
public int CategoryId { get; set; }
public virtual Category Category { get; set; }
public virtual List<CategoryItemValue> Values { get; set; }
}
public class CategoryItemValue
{
public int Id { get; set; }
public int CategoryItemId { get; set; }
public int CategoryPropertyId { get; set; }
public string Value { get; set; }
public virtual CategoryItem Item { get; set; }
public virtual CategoryProperty Property { get; set; }
}
protected override void OnModelCreating(DbModelBuilder modelBuilder)
{
// I know that the solution needs to go here!
}
似乎我需要为 CategoryItemValues 禁用 Cascade on Delete,但我不知道该怎么做。我知道我需要做类似的事情:
modelBuilder.Entity<...>() .HasRequired(...) .WithMany(...) .HasForeignKey(...) .WillCascadeOnDelete(false);
但我不能完全正确。