同一主键表的多个外键

Question

我有一个包含多个字段的表,这些字段是另一个表中主键的外键.例如 :

Fixture Id (PK)
HomeTeamId (FK to Team.TeamId)
AwayTeamId (FK to Team.TeamId)
HomeTeamCoachId (FK to Coach.CoachId)
AwayTeamCoachId (FK to Coach.CoachId)

将这些数据分成两个表HomeTeam和AwayTeam以及FixtureId的外键会更好吗？这是当前由实体框架生成的内容:

FixtureId PK
HomeTeamId int
AwayTeamId int
HomeTeamCoachId int
AwayTeamCoachId int
AwayTeam_TeamId FK
HomeTeam_TeamId FK
AwayTeamCoach_CoachId FK
HomeTeamCoach_CoachId FK

这是通过这个类生成的:

public partial class Fixture
{
    public int FixtureId { get; set; }

    //foreign key
    public int AwayTeamId { get; set; }
    //navigation properties
    public virtual Team AwayTeam { get; set; }

    //foreign key
    public int HomeTeamId { get; set; }
    //navigation properties
    public virtual Team HomeTeam { get; set; }

    //foreign key
    public int AwayCoachId { get; set; }
    //navigation properties
    public virtual Coach AwayCoach { get; set; }

    //foreign key
    public int HomeCoachId { get; set; }
    //navigation properties
    public virtual Coach HomeCoach { get; set; }
}

任何人都可以告诉我这是否是正确的方法吗？

编辑:回复Slauma

所以我的课程基本上会是这样的？或者OnModelCreating中的配置是否意味着我不需要我的Fixture类中的一些外键相关代码？

 protected override void OnModelCreating(DbModelBuilder modelBuilder)
    {
        // Entity Type Configuration
        modelBuilder.Configurations.Add(new TeamConfiguration());
        modelBuilder.Configurations.Add(new CoachConfiguration());
        modelBuilder.Configurations.Add(new FixtureConfiguration());

        modelBuilder.Entity<Fixture>()
            .HasRequired(f => f.AwayTeam)
            .WithMany()
            .HasForeignKey(f => f.AwayTeamId)
            .WillCascadeOnDelete(false);

        modelBuilder.Entity<Fixture>()
            .HasRequired(f => f.HomeTeam)
            .WithMany()
            .HasForeignKey(f => f.HomeTeamId)
            .WillCascadeOnDelete(false);

        modelBuilder.Entity<Fixture>()
            .HasRequired(f => f.AwayCoach)
            .WithMany()
            .HasForeignKey(f => f.AwayCoachId)
            .WillCascadeOnDelete(false);

        modelBuilder.Entity<Fixture>()
            .HasRequired(f => f.HomeCoach)
            .WithMany()
            .HasForeignKey(f => f.HomeCoachId)
            .WillCascadeOnDelete(false);
    }

public partial class Fixture
{
    public int FixtureId { get; set; }
    public string Season { get; set; }
    public byte Week { get; set; }

    //foreign key
    public int AwayTeamId { get; set; }
    //navigation properties
    public virtual Team AwayTeam { get; set; }

    //foreign key
    public int HomeTeamId { get; set; }
    //navigation properties
    public virtual Team HomeTeam { get; set; }

    //foreign key
    public int AwayCoachId { get; set; }
    //navigation properties
    public virtual Coach AwayCoach { get; set; }

    //foreign key
    public int HomeCoachId { get; set; }
    //navigation properties
    public virtual Coach HomeCoach { get; set; }

    public byte AwayTeamScore { get; set; }
    public byte HomeTeamScore { get; set; }
}

Answer 1

显然,EF不会检测您的int属性,如AwayTeamId导航属性的外键,AwayTeam因为主键属性Team不是,Id但是TeamId.如果它们被命名为AwayTeamTeamId或者如果主键属性Team具有名称,它可能会检测到FK Id.

如果您不想根据EF约定更改这些属性名称,则可以使用数据注释定义FK:

[ForeignKey("AwayTeam")]
public int AwayTeamId { get; set; }
public virtual Team AwayTeam { get; set; }

// the same for the other three FKs

或者流利的API:

modelBuilder.Entity<Fixture>()
    .HasRequired(f => f.AwayTeam)
    .WithMany()
    .HasForeignKey(f => f.AwayTeamId)
    .WillCascadeOnDelete(false);

// the same for the other three FKs

我已禁用级联删除,因为默认情况下它将启用所需的关系.但是因为你有两个必需的关系到Team表(以及Coach表),它将导致两个级联删除路径Fixture到Team和Coach.多级联删除路径被禁止在SQL Server中,所以你必须禁用级联删除了两者之间的关系中的至少一个Fixture与Team(之间Fixture和Coach).