Question

我变得如此困惑！这是我第一次使用MVC3和EF Code First。我收到以下错误：

在表'CityUsers'上引入FOREIGN KEY约束'FK_dbo.CityUsers_dbo.Cities_CityID'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。

我一直在努力工作几个小时，尽我所能，但却无法处理它！

情景是，有一个 Man 类，派生用户。 每个用户只属于一个城市。用户我的意思是管理员用户。每个城市都可以插入/更新多个城市，每个城市一次只能由一个用户修改。我创建了第三个名为'CityUser'的表来跟踪修改城市记录的用户。

这是我的模型类：

public class Man
{
    [Key]
    [DatabaseGenerated(System.ComponentModel.DataAnnotations.Schema.DatabaseGeneratedOption.Identity)]
    public long ID { get; set; }
    //------------------------------------------------------------//
    [Required, MaxLength(20)]
    [LocalizedAttribute("FName")]
    public string FName { get; set; }
    //------------------------------------------------------------//
    [Required, MaxLength(20)]
    [LocalizedAttribute("LastName")]
    public string LastName { get; set; }
    //------------------------------------------------------------//
    [Required]
    [RegularExpression("^[0-9]+$", ErrorMessageResourceName = "ErrorOnlyNumbers", ErrorMessageResourceType = typeof(MAHAL_E_MA_Model.Properties.Resources))]
    [LocalizedAttribute("Mobile")]
    public string Mobile { get; set; }
    //------------------------------------------------------------//
    [LocalizedAttribute("Phone")]
    [RegularExpression("^[0-9]+$", ErrorMessageResourceName = "ErrorOnlyNumbers", ErrorMessageResourceType = typeof(MAHAL_E_MA_Model.Properties.Resources))]
    public string HomePhone { get; set; }
    //------------------------------------------------------------//
    [RegularExpression("^[0-9]+$")]
    [LocalizedAttribute("IDCardNumber")]
    public string IDCardNumber { get; set; }
    //------------------------------------------------------------//
    [RegularExpression("^[0-9]+$")]
    [LocalizedAttribute("NationalCode")]
    public string NationalCode { get; set; }
    //------------------------------------------------------------//
    [MaxLength(10)]
    [LocalizedAttribute("DOB")]
    public int DOB { get; set; }
    //------------------------------------------------------------//
    [Required]
    public int CityID { get; set; }
    [ForeignKey("CityID")]
    public virtual City CityParent { get; set; }
    //------------------------------------------------------------//
    [MaxLength(100)]
    [LocalizedAttribute("Address")]
    public string Address { get; set; }
    //------------------------------------------------------------//
    [LocalizedAttribute("PostalCode")]
    public string PostalCode { get; set; }
    //------------------------------------------------------------//
    [MaxLength(255)]
    [LocalizedAttribute("PhotoPath")]
    public string PhotoPath { get; set; }
}

 public class User : Man
{
    [MaxLength(20)]
    [LocalizedAttribute("Username")]
    public string UserName { get; set; }
    //------------------------------------------------------------//
    [DataType(DataType.Password)]
    [MaxLength(100), MinLength(6, ErrorMessageResourceType = typeof(MAHAL_E_MA_Model.Properties.Resources), ErrorMessageResourceName = "ErrorPasswordLength")]
    [LocalizedAttribute("Password")]
    public string Password { get; set; }
    //------------------------------------------------------------//
    [DataType(DataType.Password)]
    [Compare("Password", ErrorMessageResourceType = typeof(MAHAL_E_MA_Model.Properties.Resources), ErrorMessageResourceName = "ErrorConfirmPassword")]
    [LocalizedAttribute("ConfirmPassword")]
    public string ConfirmPassword { get; set; }
    //------------------------------------------------------------//
    [DataType(DataType.EmailAddress, ErrorMessageResourceType = typeof(MAHAL_E_MA_Model.Properties.Resources), ErrorMessageResourceName = "ErrorEmailInvalid")]
    [MaxLength(20)]
    [RegularExpression(@"[a-zA-Z0-9._%+-]+@[a-zA-Z0-9.-]+\.[a-zA-Z]{2,}")]
    [LocalizedAttribute("Email")]
    public string Email { get; set; }
    //------------------------------------------------------------//
    [MaxLength(30)]
    [LocalizedAttribute("Title")]
    public string Title { get; set; }
    //------------------------------------------------------------//
    [MaxLength(10)]
    [LocalizedAttribute("HireDate")]
    public int HireDate { get; set; }
    //------------------------------------------------------------//
    [LocalizedAttribute("ReportsTo")]
    public long ReportsTo { get; set; }
    [ForeignKey("ReportsTo")]
    public virtual IList<User> ReportsChild { get; set; }
}

public class City
{
    [Key]
    [DatabaseGenerated(System.ComponentModel.DataAnnotations.Schema.DatabaseGeneratedOption.Identity)]
    public int CityID { get; set; }
    //------------------------------------------------------------//
    [Required, MaxLength(20)]
    [LocalizedAttribute("Name")]
    public string Name { get; set; }
    //------------------------------------------------------------//
    [LocalizedAttribute("PhoneCode")]
    public int PhoneCode { get; set; }
    //------------------------------------------------------------//
    [Required, MaxLength(10)]
    public int ModifiedDate { get; set; }
}

public class CityUser
{
    [Key]
    [DatabaseGenerated(System.ComponentModel.DataAnnotations.Schema.DatabaseGeneratedOption.Identity)]
    public int CityUserID { get; set; }
    //------------------------------------------------------------//
    [Required]
    public long ModifiedByUserID { get; set; }
    [ForeignKey("ModifiedByUserID")]
    public virtual User OperatorUser { get; set; }
    //------------------------------------------------------------//
    [Required]
    public int CityID { get; set; }
    [ForeignKey("CityID")]
    public virtual City City { get; set; }
}

但是当EF5用于创建数据库时，前面提到的错误就出来了！我该怎么办？我已经阅读了很多关于数据模型的博客的博客。但仍然无法解决这个错误....顺便说一句，我想用 DataAnnotations 声明关系。 / p>

现在有谁能让我摆脱这个问题??? !!!! ：（

此致

Answer 1

最后，我可以在接下来的几个小时和很多的努力下过来，通过这种方式永远不会忘记这个概念！：d 解决方案发现：

modelBuilder.Conventions.Remove<OneToManyCascadeDeleteConvention>();

使用EF Code First的循环和多个级联路径

1 个答案: