C#•5mo ago

OnModelCreating dont work in Memory Database

I try create API for list menu.

public class Context : DbContext
{
    public Context(DbContextOptions<Context> options)
        : base(options)
    {
    }

    public DbSet<Sandwich> Sandwiches { get; set; } = null!;
    public DbSet<Extra> Extras { get; set; } = null!;
    public DbSet<Order> Orders { get; set; } = null!;

    protected override void OnModelCreating(ModelBuilder modelBuilder)
    {
        Console.WriteLine("OnModelCreating Executado");
        // Gerando a seed de dados
        modelBuilder.Entity<Sandwich>().HasData(
            new Sandwich { Id = 1, Name = "X Burger", Price = 5.00m },
            new Sandwich { Id = 2, Name = "X Egg", Price = 4.50m },
            new Sandwich { Id = 3, Name = "X Bacon", Price = 7.00m }
        );

        modelBuilder.Entity<Extra>().HasData(
            new Extra { Id = 1, Name = "Fries", Price = 2.00m },
            new Extra { Id = 2, Name = "Soft Drink", Price = 2.50m }
        );
    }
}

public class Context : DbContext
{
    public Context(DbContextOptions<Context> options)
        : base(options)
    {
    }

    public DbSet<Sandwich> Sandwiches { get; set; } = null!;
    public DbSet<Extra> Extras { get; set; } = null!;
    public DbSet<Order> Orders { get; set; } = null!;

    protected override void OnModelCreating(ModelBuilder modelBuilder)
    {
        Console.WriteLine("OnModelCreating Executado");
        // Gerando a seed de dados
        modelBuilder.Entity<Sandwich>().HasData(
            new Sandwich { Id = 1, Name = "X Burger", Price = 5.00m },
            new Sandwich { Id = 2, Name = "X Egg", Price = 4.50m },
            new Sandwich { Id = 3, Name = "X Bacon", Price = 7.00m }
        );

        modelBuilder.Entity<Extra>().HasData(
            new Extra { Id = 1, Name = "Fries", Price = 2.00m },
            new Extra { Id = 2, Name = "Soft Drink", Price = 2.50m }
        );
    }
}

When i call endpoing /api/menu i see Console log, but return empty sandwich and extra. Obs: When i use EnsureCreated, workly

7 Replies

Jimmacle•5mo ago

to clarify, you're saying that when you call EnsureCreated that it works correctly? that is intended behavior, in order to apply changes you've made to your database model you either need to call EnsureCreated or use migrations

Jimmacle•5mo ago

https://learn.microsoft.com/en-us/ef/core/modeling/data-seeding

Data Seeding - EF Core

Using data seeding to populate a database with an initial set of data using Entity Framework Core

Jimmacle•5mo ago

you should be using migrations if you have any plans to evolve the model over time

Carlos DavidOP•5mo ago

Yes, i tried set directly in controller the método EnsureCreated and i See The console log two times, but return the correctly data of sandwich and extra 😅Ah ok, it's my first time with C# and I didn't know that I have one more question, if you can answer I can set EnsureCreated when i started program?

Jimmacle•5mo ago

You can but it won't work if the database already exists Migrations are a much better choice for that

Carlos DavidOP•5mo ago

Without a doubt, but I'm doing for a job and they specified that I need to use the in-memory database😭 kkkkk but the article you sent me seems very useful, I will try to implement it, thank you! with help Chat GPT, i did this

var app = builder.Build();

# region Seed de dados
using (var scope = app.Services.CreateScope())
{
    // Para banco de dados na memória é necessário fazer na mão utilizando o EnsureCreted
    // Fonte: https://learn.microsoft.com/en-us/ef/core/modeling/data-seeding
    var context = scope.ServiceProvider.GetRequiredService<Context>();
    context.Database.EnsureCreated();
}
# endregion

var app = builder.Build();

# region Seed de dados
using (var scope = app.Services.CreateScope())
{
    // Para banco de dados na memória é necessário fazer na mão utilizando o EnsureCreted
    // Fonte: https://learn.microsoft.com/en-us/ef/core/modeling/data-seeding
    var context = scope.ServiceProvider.GetRequiredService<Context>();
    context.Database.EnsureCreated();
}
# endregion

Console log show 2 times, but dont duplicate data. I ignore because its working

jcotton42•5mo ago

Why do they want you to use in-memory? EF’s in-memory database is a trap.

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OnModelCreating dont work in Memory Database