实体框架代码优先-来自同一表的两个外键

一尘不染

实体框架代码优先-来自同一表的两个外键

我刚开始使用EF代码，因此我是该主题的总入门者。

我想在团队和比赛之间建立关系：

1场比赛= 2支球队（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 Date { get; set; }

    public virtual Team HomeTeam { get; set; }
    public virtual Team GuestTeam { get; set; }
}

我得到一个例外：

引用关系将导致不允许循环引用。[约束名称= Match_GuestTeam]

如何用两个指向同一个表的外键创建这样的模型？

阅读 320

2020-05-19

共1个答案

一尘不染

尝试这个：

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

    public virtual ICollection<Match> HomeMatches { get; set; }
    public virtual ICollection<Match> AwayMatches { get; set; }
}

public class Match
{
    public int MatchId { get; set; }

    public int HomeTeamId { get; set; }
    public int GuestTeamId { get; set; }

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

    public virtual Team HomeTeam { get; set; }
    public virtual Team GuestTeam { get; set; }
}


public class Context : DbContext
{
    ...

    protected override void OnModelCreating(DbModelBuilder modelBuilder)
    {
        modelBuilder.Entity<Match>()
                    .HasRequired(m => m.HomeTeam)
                    .WithMany(t => t.HomeMatches)
                    .HasForeignKey(m => m.HomeTeamId)
                    .WillCascadeOnDelete(false);

        modelBuilder.Entity<Match>()
                    .HasRequired(m => m.GuestTeam)
                    .WithMany(t => t.AwayMatches)
                    .HasForeignKey(m => m.GuestTeamId)
                    .WillCascadeOnDelete(false);
    }
}

默认情况下，主键是映射的。球队必须有两场比赛。您不能有两个FK引用的单个集合。匹配映射没有级联删除，因为在这些自引用多对多中不起作用。

2020-05-19