DEMOMySql/MicroServices/Business/Business.Host/EntityFrameworkCore/BusinessExtMigrationDbContextFactory.cs

using Microsoft.EntityFrameworkCore;
using Microsoft.EntityFrameworkCore.Design;
using Microsoft.EntityFrameworkCore.Migrations;
using Microsoft.Extensions.Configuration;
using System;
using System.IO;

namespace Business.EntityFrameworkCore
{
    public class BusinessExtMigrationDbContextFactory: IDesignTimeDbContextFactory<BusinessExtMigrationDbContext>
    {
        public BusinessExtMigrationDbContext CreateDbContext(string[] args)
        {
            var configuration = BuildConfiguration();

            var builder = new DbContextOptionsBuilder<BusinessExtMigrationDbContext>().UseSqlServer(configuration.GetConnectionString("DOPExt"));

            return new BusinessExtMigrationDbContext(builder.Options);
        }

        private static IConfigurationRoot BuildConfiguration()
        {
            var builder = new ConfigurationBuilder()
                .SetBasePath(Path.Combine(Directory.GetCurrentDirectory()))
                .AddJsonFile("appsettings.json", optional: false);

            return builder.Build();
        }
    }
}