I use MS SQL Server and Entity Framework Core , it’s impossible to set the tables in the database correctly.

I have an Item table - this is a product. Table Order - order. Order can have many Item . Item should not store Order information. To store information about the goods in the order there is a separate table ItemOrder .

DB schema

Item

 public class Item { public int Id { get; set; } public string Name { get; set; } public double Price { get; set; } }

Order

 public class Order { public int Id { get; set; } public int UserId { get; set; } public List<Item> Items { get; set; } }

ItemOrder

 public class ItemOrder { public int ItemId { get; set; } public Item Item { get; set; } public int OrderId { get; set; } public Order Order { get; set; } }

At the moment, when creating a database, the OrderId field is added to the Item table, and I need the goods in the order to be ItemOrder in the ItemOrder table. How can I specify this in the Entity Framework Core code?

    1 answer 1

    It was possible to solve the problem, my mistake was that I did not correctly link the tables.

    Item

     public class Item { public int Id { get; set; } public string Name { get; set; } public double Price { get; set; } public List<ItemOrder> ItemOrder { get; set; } }

    Order

     public class Order { public int Id { get; set; } public int UserId { get; set; } public List<ItemOrder> ItemOrder { get; set; } }

    And in the context you need to register:

     protected override void OnModelCreating(ModelBuilder modelBuilder) { modelBuilder.Entity<ItemOrder>().HasKey(t => new {t.ItemId, t.OrderId}); modelBuilder.Entity<ItemOrder>() .HasOne(x => x.Item) .WithMany(x => x.ItemOrder) .HasForeignKey(x => x.ItemId); modelBuilder.Entity<ItemOrder>() .HasOne(x => x.Order) .WithMany(x => x.ItemOrder) .HasForeignKey(x => x.OrderId); }

    Source: metanit