相关疑难解决方法(0)

我已经搞砸了我的迁移,我用于IgnoreChanges初始迁移,但现在我想要删除所有迁移,并开始使用所有逻辑进行初始迁移.

当我删除文件夹中的迁移并尝试Add-Migration它并不生成一个完整的文件(它是空的 - 因为我上次没有做任何更改,但现在已删除,迁移).

是否有任何Disable-Migrations命令,所以我可以重新运行Enable-Migrations？

我刚开始使用EF代码,所以我在这个主题中完全是初学者.

我想在团队和比赛之间建立关系:1场比赛= 2队(主场,客场)和结果.我认为创建这样的模型很容易,所以我开始编码:

public class Team
{
    [Key]
    public int TeamId { get; set;} 
    public string Name { get; set; }

    public virtual ICollection<Match> Matches { get; set; }
}


public class Match
{
    [Key]
    public int MatchId { get; set; }

    [ForeignKey("HomeTeam"), Column(Order = 0)]
    public int HomeTeamId { get; set; }
    [ForeignKey("GuestTeam"), Column(Order = 1)]
    public int GuestTeamId { get; set; }

    public float HomePoints { get; set; }
    public float GuestPoints { get; set; }
    public DateTime …

有下面的类,并尝试在数据库中查找记录返回错误.使用C#,MVC 4,Entity Framework 4和SQL Server 2012数据库.

错误

Unable to determine the principal end of an association between the types 'FlexApp.Models.Model.Usuario' and 'FlexApp.Models.Model.Usuario'. 

The principal end of this association must be explicitly configured using either the relationship fluent API or data annotations.

类

public class Usuario
{
    [Key]
    public int UsuarioID { get; set; }
    public string Nome { get; set; }
    public int UsuCad { get; set; }        
    public int UsuAlt { get; set; }

    [ForeignKey("UsuCad")]
    public virtual Usuario UsuarioCad …

Person是包含所有用户的用户模型.更改模型包括EngineerId和ManagerId,两者都是Person ID.为什么我收到此错误？

无法在类型ProjectName.Models.Change上确定外键的复合外键排序.在复合外键属性上使用ForeignKey数据批注时,请确保使用Column数据批注或Fluent API指定顺序.

public class Change
{
    [Key]
    public int ChangeId { get; set; }

    [Required(ErrorMessage = "Change description is required.")]
    [Display(Name = "Change Description")]
    [DataType(DataType.MultilineText)]
    public string ChangeDescription { get; set; }

    [Required(ErrorMessage = "Change date is required.")]
    [Display(Name = "Date of Change")]
    [DataType(DataType.Date)]
    public DateTime ChangeDate { get; set; }

    [Required(ErrorMessage = "Time is required.")]
    [Display(Name = "Time of Change")]
    [DataType(DataType.Time)]
    public DateTime ChangeTime { get; set; }

    [Required(ErrorMessage = "Engineer name is required.")]
    [Display(Name = "Engineer")] …