C# - Migration failed for solution with 2 projects (DBContext setr in only one project)

Question

Error message:

No DbContext was found in assembly 'API_Test_Console'. Ensure that you're using the correct assembly and that the type is neither abstract nor generic.

If you take a look at projects structure:

Project "API_Test_Console" Should be responsible only for create new instances os objects and running this solution

Project "API_Test_Library" Contains all classes that will be used for this solution. Also the classes responsibles for connecting with SQL.

API_Test_Library -> SYSTEM_CONECTION.CS (where DBContext is currently set)

using API_Test_Library.Models;
using Microsoft.EntityFrameworkCore;

namespace API_Test_Library.DB;

public class SYSTEM_CONTEXT : DbContext
{

    public DbSet<Value> Values { get; set; }
    public DbSet<Category> Categories { get; set; }


    private string ConnectionString = "Data Source=(localdb)\\MSSQLLocalDB;Initial Catalog=API_Test_V0;Integrated Security=True;Connect Timeout=30;Encrypt=False;Trust Server Certificate=False;Application Intent=ReadWrite;Multi Subnet Failover=False";

    protected override void OnConfiguring(DbContextOptionsBuilder optionsBuilder)
    {
        optionsBuilder.UseSqlServer(ConnectionString);
    }

    protected override void OnModelCreating(ModelBuilder modelBuilder)
    {
        modelBuilder.Entity<Value>()
            .HasKey(a => a.Id);
        modelBuilder.Entity<Value>()
            .HasOne(a => a.Category);
        modelBuilder.Entity<Category>()
            .HasKey(a => a.Id);
        modelBuilder.Entity<Category>()
            .HasMany(a => a.Values);
        base.OnModelCreating(modelBuilder);
    }
}

Fix I know so far

Create another class at API_Test_Console -> Console_Context.CS. Like that:

Code

using API_Test_Library.Models;
using Microsoft.EntityFrameworkCore;

namespace API_Test_Console;

public class Console_CONTEXT : DbContext
{

    public DbSet<Value> Values { get; set; }

    private string ConnectionString = "Data Source=(localdb)\\MSSQLLocalDB;Initial Catalog=API_Test_V0;Integrated Security=True;Connect Timeout=30;Encrypt=False;Trust Server Certificate=False;Application Intent=ReadWrite;Multi Subnet Failover=False";

    protected override void OnConfiguring(DbContextOptionsBuilder optionsBuilder)
    {
        optionsBuilder.UseSqlServer(ConnectionString);
    }

    protected override void OnModelCreating(ModelBuilder modelBuilder)
    {
        modelBuilder.Entity<Value>()
            .HasKey(a => a.Id);

        base.OnModelCreating(modelBuilder);
    }
}

Question:

Is there another way of fixing it? Or is mandatory to have a DBContext set for each project?

Note: Projects references are set like:

To have only one DBContext set for the enrity SOLUTION.

Answer 1

To add migrations to a project containing your DbContext class, you need to select the project from the Package Manager Console's dropdown. Choose Api_Test_Library.

By the way, what's up with the weird naming? SYSTEM_CONTEXT? SYSTEM_CONECTION?