PostgreSQL 关系冲突

Question

    public class Event
    {
        [Key]
        [DatabaseGenerated(DatabaseGeneratedOption.Identity)]
        public int Id { get; set; }

        public Guid GuidId { get; set; }

        public virtual EventType Type { get; set; }

        public string Title { get; set; }

        public string Desc { get; set; }

        public Guid Author { get; set; }

        public bool IsAllowed { get; set; }

        public DateTime DateStart { get; set; }

        public DateTime DateEnd { get; set; }

        public string Place { get; set; }

        public Guid Responsible { get; set; }

        public DateTime DateCreated { get; set; }

        public DateTime DateUpdated { get; set; }

        public virtual ICollection<EventСomment> Comments { get; set; }

        public virtual ICollection<EventWorker> Workers { get; set; }

        public virtual ICollection<EventMember> Members { get; set; } 

        public virtual ICollection<EventInvitation> invitations { get; set; }

     public class EventInvitation
     {
        [Key]
        [DatabaseGenerated(DatabaseGeneratedOption.Identity)]
        public int Id { get; set; }

        public Guid GuidId { get; set; }

        public string Type { get; set; }

        public int EventId { get; set; }

        [JsonIgnore]
        public virtual Event Event { get; set; }

        public Guid Persone { get; set; }

        public string Comment { get; set; }

        public Guid Author { get; set; }

        public bool IsApproved { get; set; }

        public DateTime DateCreated { get; set; }

        public DateTime DateUpdated { get; set; }
    }

    public class EventMember
    {
        [Key]
        [DatabaseGenerated(DatabaseGeneratedOption.Identity)]
        public int Id { get; set; }

        public Guid GuidId { get; set; }

        public int EventId { get; set; }

        [JsonIgnore]
        public virtual Event Event { get; set; }

        public Guid Person { get; set; }

        public string Comment { get; set; }

        public Guid Author { get; set; }

        public bool IsApproved { get; set; }

        public DateTime DateCreated { get; set; }

        public DateTime DateUpdated { get; set; }
    }

这些是我用于 PostgreSQL 数据库的 3 个实体框架模型。正如您所看到的，这是主要的事件模型，其中包含 EventInvitation 和 EventMember 的集合。

问题是我想在EventInvitation和EventMember之间建立1对1的关系，但是我的所有尝试都会导致与Event的一些关键冲突，我不知道如何正确地做到这一点。 也许我的想法从根本上来说是错误的，我只是试图做不可能的事。无论如何，这是我的上下文类来显示我已经拥有的连接：

    public class DataContext: DbContext
    {

        public DbSet<Event> Events{ get; set; }
        public DbSet<EventInvitation> Invitations{ get; set; }
        public DbSet<EventMember> Members { get; set; }
        public DbSet<EventType> Types { get; set; }
        public DbSet<EventWorker> Worker { get; set; }
        public DbSet<EventСomment> Comments { get; set; }
        public DbSet<Relation> Relations { get; set; }

        public DataContext(DbContextOptions options) : base(options)
        {
        }

        protected override void OnModelCreating(ModelBuilder modelBuilder)
        {
            modelBuilder.ApplyConfigurationsFromAssembly(typeof(DataContext).Assembly);
            base.OnModelCreating(modelBuilder);

            modelBuilder.Entity<Event>()
                .HasMany(p => p.Members)
                .WithOne(c => c.Event)
                .HasForeignKey(c => c.EventId);

            modelBuilder.Entity<Event>()
                .HasMany(p => p.invitations)
                .WithOne(c => c.Event)
                .HasForeignKey(c => c.EventId);

            modelBuilder.Entity<Event>()
                .HasMany(p => p.Comments)
                .WithOne(c => c.Event)
                .HasForeignKey(c => c.EventId);
        }

Answer 1

要在

EventInvitation

和

EventMember

之间建立 1:1 关系，您需要决定主要实体和从属实体。依赖实体的主键也将充当主体实体的外键。

对于此示例，我们假设

EventInvitation

是主要实体，

EventMember

是从属实体。这意味着对于每个

EventInvitation

，最多可以有一个

EventMember

，并且

EventMember

的主键也将是

EventInvitation

的外键。

设置方法如下：

1. 更新模型：

public class EventInvitation
{
    // ... other properties ...

    public virtual EventMember Member { get; set; }
}

public class EventMember
{
    [Key]
    [ForeignKey("EventInvitation")] // This indicates that the primary key is also a FK to EventInvitation
    public int Id { get; set; }

    // ... other properties ...

    public virtual EventInvitation Invitation { get; set; }
}

2. 在您的上下文中更新

   OnModelCreating

   方法：

protected override void OnModelCreating(ModelBuilder modelBuilder)
{
    // ... other configurations ...

    modelBuilder.Entity<EventInvitation>()
        .HasOne(i => i.Member)
        .WithOne(m => m.Invitation)
        .HasForeignKey<EventMember>(m => m.Id);  // Indicates that EventMember's Id is the FK to EventInvitation

    // ... other configurations ...
}

这样做：

• 您是说每个

  EventInvitation

  有一个

  EventMember

  ，并且

  EventMember

  的主键也充当

  EventInvitation

  的外键。
• 您可以使用

  EventInvitation

  导航属性从

  EventMember

  导航到其对应的

  Member

  ，反之亦然，使用

  Invitation

  导航属性。

请记住，对于 1:1 关系，您需要确保数据遵守此约束。创建

EventMember

时，其

Id

应与现有

Id

的

EventInvitation

匹配。

如果您决定

EventMember

应该是主要实体，您将反转配置。