自動檢索物體框架外鍵關系模型

我正在開發餐廳應用程式。我有一個餐廳模型和一個桌子模型。

namespace Restaurant.Models
{
    [Table("Restaurant")]
    public class RestaurantModel
    {
        [Key]
        [Column("id")]
        public int Id { get; set; }
        
        [Column("name")]
        public string Name { get; set; }
        
        [Column("telephone_number")]
        public int TelephoneNumber { get; set; }
        
        [NotMapped]
        public List<TableModel> Tables;
        
        public RestaurantModel()
        {
            Tables = new List<TableModel>();
        }
    }
}

namespace Restaurant.Models
{
    [Table("Table")]
    public class TableModel
    {
        [Key]
        [Column("id")]
        public int Id { get; set; }

        [ForeignKey("restaurant_id")]
        [Required] [NotNull]
        public int RestaurantId { get; set; }
        
        [Column("available_seats")]
        public int AvailableSeats { get; set; }
        
        [Column("is_indoors")]
        public bool IsIndoors { get; set; }
    }
}

我在 Restaurant 和 Table 之間有依賴關系：

以下是物體框架通過我的背景關系為我創建的列和鍵：

最后，這是我的 Context 類：

namespace Restaurant.Data
{
    public class RestaurantContext : DbContext
    {
        public RestaurantContext(DbContextOptions<RestaurantContext> options) : base(options)
        {
        }
        
        public DbSet<RestaurantModel> Restaurants { get; set; }
        public DbSet<TableModel> Tables { get; set; }
        public DbSet<GuestModel> Guests { get; set; }

        protected override void OnModelCreating(ModelBuilder modelBuilder)
        {
            modelBuilder.Entity<RestaurantModel>().ToTable("Restaurant");
            modelBuilder.Entity<TableModel>().ToTable("Table");
            modelBuilder.Entity<GuestModel>().ToTable("Guest");

            modelBuilder.Entity<TableModel>()
                .HasOne<RestaurantModel>();
        }
    }
}

When I retrieve a restaurant, I want the corresponding tables to be retrieved inside of the TableModel List. Currently, when I retrieve a Restaurant, it will not retrieve any corresponding Tables. This makes sense to me, as I have not properly connected the relationship for EntityFramework to recognize it. I have tried to look online how to do it, consulting guides on setting up Foreign Key relationships and such. I cannot find the information I am looking for, due to a lack of basic knowledge. The answers I can find do not make sense to me because I do not understand what they are doing or how they are doing it.

Could anyone point me in the right direction or tell me what I am doing wrong?

uj5u.com熱心網友回復：

為您的課程添加關系

    [Table("Restaurant")]
    public class Restaurant
    {
        [Key]
        [Column("id")]
        public int Id { get; set; }
        
        [Column("name")]
        public string Name { get; set; }
        
        [Column("telephone_number")]
        public int TelephoneNumber { get; set; }
      
        public virtual ICollection<Table> Tables { get; set; }
        
    }
}

    [Table("Table")]
    public class Table
    {
        [Key]
        [Column("id")]
        public int Id { get; set; }

         
        public int? RestaurantId { get; set; }
         public virtual Restourant Restaurant { get; set; }

        [Column("available_seats")]
        public int AvailableSeats { get; set; }
        
        [Column("is_indoors")]
        public bool IsIndoors { get; set; }
    }
}

并且由于您使用的是 Net core 5 我認為您沒有任何導航屬性或流暢的 API

洗掉舊的遷移檔案夾并干凈地遷移到 db

在此之后，您可以嘗試使用此代碼進行測驗

var restourant= context.Restourants.Include(r=> r.Tables).FirstOrDefault(r=>r.Id==id);

它應該回傳一個帶有表串列的餐廳

標籤：c# sql entity-framework

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