Two migration sets with two DBContext generate an error[Answered] RSS

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  hanidraidi

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  Two migration sets with two DBContext generate an error

  Jul 19, 2020 07:13 AM|hanidraidi|LINK

  I am working with ef core 3.1.4 and .net core 3.1.4, and trying to implement migration with two different database providers using two migration sets, I followed the documentation, and added a new DbContext for Sqlite, and when adding a migration I get the following error:

  Unable to create an object of type 'MySqliteDbContext'. For the different patterns supported at design time, see https://go.microsoft.com/fwlink/?linkid=851728

  Here is my Datacontext:

  using System;
  using Domain;
  using Microsoft.AspNetCore.Identity.EntityFrameworkCore;
  using Microsoft.EntityFrameworkCore;
  
  namespace Persistence
  {
      public class DataContext : IdentityDbContext<AppUser>
      {
          public DataContext(DbContextOptions options) : base(options)
          {
          }
  
          public DbSet<App> Apps { get; set; }
          protected override void OnModelCreating(ModelBuilder builder)
          {
              base.OnModelCreating(builder);
          }
      }
  }
  

  and here is my new DBContext for Sqlite:

  using Microsoft.EntityFrameworkCore;
  
  namespace Persistence
  {
      public class MySqliteDbContext : DataContext
      {
          public MySqliteDbContext(DbContextOptions options) : base(options)
          {
          }
  
          protected override void OnConfiguring(DbContextOptionsBuilder options)
          => options.UseSqlite("Data source=db.db");
      }
  }
  

  and this is how I configure services in startup.cs in my API project:

  if (Configuration["Provider"] == "SQLlite")
              {
                  services.AddDbContext<DataContext>(opt =>
                      opt.UseSqlite(Configuration.GetConnectionString("SQLlite")));
              }
  else if (Configuration["Provider"] == "MSSQL")
              {
                  services.AddDbContext<DataContext>(opt =>
                      opt.UseSqlServer(Configuration.GetConnectionString("SQLServerConnection")));
              }
   else
              { throw new ArgumentException("Not a valid database type"); }
  

  Below is appsettings.json in my starter API project:

  {
    "Provider": "SQLlite",
    "ConnectionStrings": {
      "SQLlite": "Data source=db.db",
      "SQLServerConnection": "Server=(localdb)\\mssqllocaldb;Database=db;Trusted_Connection=True;MultipleActiveResultSets=true",
    },
    "Logging": {
      "LogLevel": {
        "Default": "Information",
        "Microsoft": "Warning",
        "Microsoft.Hosting.Lifetime": "Information"
      }
    },
    "AllowedHosts": "*"
  }
  
  

  I add migration by running the following comand:
  dotnet ef migrations add InitialCreate --context MySqliteDbContext --output-dir Migrations/SqliteMigrations -p Persistence -s API

  What might be the issue here?
  Any help is highly appreciated

  Kind Regards,
  Hani

• • Reply
  mgebhard

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  Re: Two migration sets with two DBContext generate an error

  Jul 19, 2020 12:08 PM|mgebhard|LINK

  I don't get the design and I don't think it will work well.  Anyway, your MySqlContext is hardcoded.

  namespace Persistence
  {
      public class MySqliteDbContext : DataContext
      {
          public MySqliteDbContext(DbContextOptions options) : base(options)
          {
          }
  
          protected override void OnConfiguring(DbContextOptionsBuilder options)
          => options.UseSqlite("Data source=db.db");
      }
  }

• • Reply
  hanidraidi

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  7 Posts

  Re: Two migration sets with two DBContext generate an error

  Jul 20, 2020 07:24 AM|hanidraidi|LINK

  May you please elaborate more what should I do to clarify the issue?

  Kind Regards,

• • Reply
  yij sun

  Contributor

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  1568 Posts

  Re: Two migration sets with two DBContext generate an error

  Jul 21, 2020 08:43 AM|yij sun|LINK

  Hi hanidraidi,

  Accroding to your description,as far as I think,you could do this:

  1.Create a constructor argument.

  2. Initialize DbContextOptions within the context and override the OnConfiguring method and call the methods on the provided DbContextOptionsBuilderConstructor argument.

  3.Use DbContext with dependency injection.

  More details,you could refer to below article:

  https://docs.microsoft.com/en-us/ef/core/miscellaneous/configuring-dbcontext

  Best regards,

  Yijing Sun

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• • Reply
  hanidraidi

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  Re: Two migration sets with two DBContext generate an error

  Jul 22, 2020 09:38 AM|hanidraidi|LINK

  Hello Yijing Sun,

  I explored this link, but the error still appears. I found the solution in this link, and it worked out finally.

  You valuable help is highly appreciated,

  Hani