C#•6mo ago

✅ List<KeyValuePair<Trader, long>> requires primary key to be defined

This is my main model i'm trying to pass

public class Item
{
    [Key]
    public int Id { get; set; }
    public string Name { get; set; }
    public List<KeyValuePair<Trader, long>> TraderPrices { get; set; }
}

public class Item
{
    [Key]
    public int Id { get; set; }
    public string Name { get; set; }
    public List<KeyValuePair<Trader, long>> TraderPrices { get; set; }
}

with Trader as

[Keyless]
public class Trader
{
    public int Id { get; set; }
    public string Name { get; set; }
    public bool IsTeTrader { get; set; }
    public bool IsAwTrader { get; set; }
}

[Keyless]
public class Trader
{
    public int Id { get; set; }
    public string Name { get; set; }
    public bool IsTeTrader { get; set; }
    public bool IsAwTrader { get; set; }
}

with a basic database

class ItemDb : DbContext
{
    public ItemDb(DbContextOptions<ItemDb> options)
        : base(options) { }
    
    public DbSet<Item> Items => Set<Item>();
}

class ItemDb : DbContext
{
    public ItemDb(DbContextOptions<ItemDb> options)
        : base(options) { }
    
    public DbSet<Item> Items => Set<Item>();
}

for some reason, passing a Item class through this this method

db.Items.Add(itemInput);
await db.SaveChangesAsync();
return Results.Created($"/items/{itemInput.Id}", itemInput);

db.Items.Add(itemInput);
await db.SaveChangesAsync();
return Results.Created($"/items/{itemInput.Id}", itemInput);

throws the error in the title is there a way to set List<KeyValuePair<Trader, long>> to be keyless?

6 Replies

Angius•6mo ago

How would you expect a List<KeyValuePair<Trader, long>> to be represented in the database? Also, what database are you using?

PIEOP•6mo ago

EntityFrameworkCore.InMemory

Angius•6mo ago

Right, so it probably does not support JSON columns

PIEOP•6mo ago

ah... would there be an alternative way to store something like this than?

{
  "Id": 123,
  "Name": "123",
  "TraderPrices": [
    {
      "Key": {
        "Id": 123,
        "Name": "123",
        "IsTeTrader": false,
        "IsAwTrader": false
      },
      "Value": 123
    }
  ]
}

{
  "Id": 123,
  "Name": "123",
  "TraderPrices": [
    {
      "Key": {
        "Id": 123,
        "Name": "123",
        "IsTeTrader": false,
        "IsAwTrader": false
      },
      "Value": 123
    }
  ]
}

with proper order? or would I need to use something else?

Angius•6mo ago

I'd rethink your schema completely It's a relational database, so use that fact No need for the whole trader to be a key anywhere An ID is enough I'd have a Trader, an Item, and a TraderPrice TraderPrice referencing both item and trader Something like

public class Item
{
    public int Id { get; set; }
    public string Name { get; set; }
    public List<TraderPrice> TraderPrices { get; set; }
}

public class Trader
{
    public int Id { get; set; }
    public string Name { get; set; }
    public bool IsTeTrader { get; set; }
    public bool IsAwTrader { get; set; }
    public List<TraderPrice> TraderPrices { get; set; }
}

public class TraderPrice
{
    public Item Item { get; set; }
    public int ItemId { get; set; }
    public Trader Trader { get; set; }
    public int TraderId { get; set; }
    public decimal Price { get; set; }
}

public class Item
{
    public int Id { get; set; }
    public string Name { get; set; }
    public List<TraderPrice> TraderPrices { get; set; }
}

public class Trader
{
    public int Id { get; set; }
    public string Name { get; set; }
    public bool IsTeTrader { get; set; }
    public bool IsAwTrader { get; set; }
    public List<TraderPrice> TraderPrices { get; set; }
}

public class TraderPrice
{
    public Item Item { get; set; }
    public int ItemId { get; set; }
    public Trader Trader { get; set; }
    public int TraderId { get; set; }
    public decimal Price { get; set; }
}

Something like that

PIEOP•6mo ago

ok thank you o/

Gaming

Programming

✅ List<KeyValuePair<Trader, long>> requires primary key to be defined