I'm having a problem with many-to-many relationships in a pizzeria system I'm developing.
I have an entity called "Payament" that has a list of Pizzas and a list of Drinks.
ex:
public class Payament
{
public string? PayamentId { get; set; }
public virtual List<Pizza> Pizzas { get; set; }
public virtual List<Drink> Drinks { get; set; }
public string? CPFId { get; set; }
[JsonIgnore]
public virtual Client? Client { get; set; }
public double? TotalPay { get; set; }
public DateTime DateTransaction { get; set; }
public virtual StatusOrder StatusOrder { get; set; }
public Payament()
{
Pizzas = new List<Pizza>();
Drinks = new List<Drink>();
DateTransaction = DateTime.Now;
StatusOrder = StatusOrder.CARRINHO;
}
}
Also, I have two entities Pizza and Drink.
ex:
public class Pizza : IItem
{
public int Id { get; set; }
public string Name { get; set; }
public string Description { get; set; }
public int Quantity { get; set; }
public double Value { get; set; }
[JsonIgnore]
public virtual List<Payament> Payament { get; set; }
public Pizza()
{
Payament = new List<Payament>();
}
}
public class Drink : IItem
{
public int Id { get; set; }
public string Name { get; set; }
public string Description { get; set; }
public int Quantity { get; set; }
public double Value { get; set; }
[JsonIgnore]
public virtual List<Payament> Payament { get; set; }
public Drink()
{
Payament = new List<Payament>();
}
}
These classes are configured as many-to-many in OnModelCreating()... Drink:
builder.HasMany(h => h.Payament)
.WithMany(d => d.Drinks);
Pizza:
builder.HasMany(h => h.Payament)
.WithMany(p => p.Pizzas);
Payament:
builder.HasMany(p => p.Pizzas)
.WithMany(p => p.Payament);
builder.HasMany(d => d.Drinks)
.WithMany(d => d.Payament);
Migrations were generated, all right. But when I go to send a payment, I get this error:
MySqlException: Cannot add or update a child row: a foreign key constraint fails (pizzaroller.drinkpayament, CONSTRAINT FK_DrinkPayament_Payament_PayamentId FOREIGN KEY (PayamentId) REFERENCES payament (PayamentId) ON DELETE CASCADE)
What I believe it could be: If I'm not mistaken, a drinkpayament table and a pizzapayament table are created where the primary keys between the relations are joined.
And in this case, "Payament" has a primary key of type string, while items "Pizza" and "Drink" have a primary key of type int.
The conflict is likely to be found in this divergence. I could be wrong, of course. So I would like to know how I can solve this problem. And also, if possible, tips on how I can work with existing items for sale and relate them to a payment.
Project is on github if you want to take a look: https://github.com/newhobbye/pizza-roller-api
This project is for the exercise of knowledge and some patterns that I will implement to practice. I accept any kind of criticism! A big hug and many thanks!