c# - MVC 中的关系数据库映射

Question

对于代码量，我深表歉意，但我只需要对 [ForeignKey("XXX") 的映射和使用进行一些确认。正确与否。

在像 Department 和 Depot 这样的类中，我需要这些行 public int DepartmentID { get; set; }或者当数据插入数据库时​​它们会自动编号。 (DepartmentID = 1(人力资源)，DepotID = 2(洛杉矶)

这是我的实体图。

用户.cs

public class User
{

    public int UserID { get; set; }
    [StringLength(50, MinimumLength = 1)]
    public string LastName { get; set; }
    [StringLength(50, MinimumLength = 1, ErrorMessage = "First name cannot be longer than 50 characters.")]

    [Column("FirstName")]
    public string FirstMidName { get; set; }

    [DataType(DataType.Date)]
    [DisplayFormat(DataFormatString = "{0:yyyy-MM-dd}", ApplyFormatInEditMode = true)]
    public DateTime EnrollmentDate { get; set; }

    public string FullName
    {
        get { return LastName + ", " + FirstMidName; }
    }
    public int AdministratorID { get; set; }
    [ForeignKey("AdministratorID")]
    public virtual Administrator Administrator { get; set; }

    public int DepartmentID { get; set; }
    [ForeignKey("DepartmentID")]
    public virtual Department Department { get; set; }


    public int DepotID { get; set; }
    [ForeignKey("DepotID")]
    public virtual Depot Depot { get; set; }

    public int TicketID { get; set; }
    //Setting up relationships A use can apply for any number of tickets, so Tickets is defined as a collection of Ticket entities.
    public virtual ICollection<Ticket> Users { get; set; }

}

票务.cs

public class Ticket
{
    public string Issue { get; set; } 
    [DisplayFormat(NullDisplayText = "No Priority")]
    public Priority? Priority { get; set; }
    //Category One to Many Ticket
    public int CategoryID { get; set; }
    [ForeignKey("CategoryID")]
    public virtual Category Category { get; set; }
    //User (One to Many) Ticket
    public int UserID { get; set; }
    public int TicketID { get; set; }
    [ForeignKey("TicketID")]
    public virtual User User { get; set; }
    public int AdminID { get; set; }
    public virtual ICollection<Administrator> Administrators { get; set; }

}

Depot.cs

public class Depot
{
    public int DepotID { get; set; }

    [StringLength(50, MinimumLength = 3)]
    public string Name { get; set; }

    public virtual ICollection<User> Users { get; set; }

}

部门.cs

public class Department
{
    public int DepartmentID { get; set; }

    [StringLength(50, MinimumLength = 3)]
    public string Name { get; set; }

    public virtual ICollection<User> Users { get; set; }
}

类别.cs

public class Category
{
    [DatabaseGenerated(DatabaseGeneratedOption.None)]
    public int CategoryID { get; set; }
    public string Title { get; set; }

    public virtual ICollection<Ticket> Tickets { get; set; }
}

管理员.cs

    public class Administrator
{
    [Key, ForeignKey("User")]
    public int UserID { get; set; }
    public int AdminID { get; set; }
    public int TicketID { get; set; }        
    [StringLength(50)]
    public string AdminRole { get; set; }
    public virtual ICollection<Ticket> Tickets { get; set; }
    public virtual User User { get; set; }
}

Answer 1

ID属性将成为该类对应的数据库表的主键列。默认情况下， Entity Framework 将名为 ID 或 classnameID 的属性解释为主键。

请参阅下面的 Depot 和 User 关系(注意 User 中的 DepotID 和 Depot 如何标记为虚拟以启用延迟加载)

public class Depot
{      
    public int DepotID { get; set; }

    [StringLength(50, MinimumLength = 3)]
    public string Name { get; set; }

    public virtual ICollection<User> Users { get; set; }

}

public class User
{

    public int UserID { get; set; }
    [StringLength(50, MinimumLength = 1)]
    public string LastName { get; set; }
    [StringLength(50, MinimumLength = 1, ErrorMessage = "First name cannot be longer than 50 characters.")]

    [Column("FirstName")]
    public string FirstMidName { get; set; }

    [DataType(DataType.Date)]
    [DisplayFormat(DataFormatString = "{0:yyyy-MM-dd}", ApplyFormatInEditMode = true)]
    public DateTime EnrollmentDate { get; set; }

    public string FullName
    {
        get { return LastName + ", " + FirstMidName; }
    }
    public int AdministratorID { get; set; }
    public virtual Administrator Administrator { get; set; }

    public int DepartmentID { get; set; }
    public virtual Department Department { get; set; }

    public virtual int DepotID { get; set; }

    [ForeignKey("DepotID")]
    public virtual Depot Depot { get; set; }

    public int TicketID { get; set; }
    public virtual ICollection<Ticket> Users { get; set; }

}