entity-framework - 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 2 个表 HomeTeam 和 AwayTeam 并使用 FixtureId 的外键会更好吗？这是当前由 Entity Framework 生成的:

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

这是通过此类生成的:

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; }
}

谁能告诉我这是否是正确的方法？

编辑:回复斯劳玛

所以我的类(class)基本上是这样的？或者 OnModelCreating 中的配置是否意味着我不需要 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 不会将 int 属性(例如 AwayTeamId)检测为导航属性(例如 AwayTeam)的外键，因为主键属性Team 中的不是 Id 而是 TeamId。如果 FK 的命名类似于 AwayTeamTeamId，或者 Team 中的主键属性的名称为 Id，那么它可能会检测到 FK。

如果您不想根据 EF 约定更改这些属性名称，您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 Fluent 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，因为默认情况下将为所需关系启用它。但是，由于您与 Team 表(以及 Coach 表)有两个必需的关系，因此会导致来自 Fixture 的两个级联删除路径致团队和教练。 SQL Server 中禁止多个级联删除路径，因此您必须对 Fixture 和 Team 之间(以及 Fixture 和 教练)。