Now we are all set to create our first Entity Framework Core migration package and create our database.

We want to start out with something simple so we want to first set and get the connection string for the database. In Asp.Net Core there's a configuration file called appSettings.json, we are going to a our MySQL connection string in this file so that our Asp.Net Core application can connect to our MySQL database.

Open the appSettings.json file and add the following lines after the first { character

  "ConnectionStrings": {

	"DefaultConnection":"Server=localhost; Database=acmebank; Uid=devuser; Pwd=P@ssw0rd"

},
  

The completed file should look like the following

  {

  "ConnectionStrings": {

	"DefaultConnection":"Server=localhost; Database=acmebank; Uid=devuser; Pwd=P@ssw0rd"

},

  "Logging": {

    "LogLevel": {

      "Default": "Information",

      "Microsoft": "Warning",

      "Microsoft.Hosting.Lifetime": "Information"

    }

  },

  "AllowedHosts": "*"

}

  

Now we are ready to write some code to create our database using the code first approach.  First create a folder at the root of the project call Models, and create a class call Value.  This class will be used by Entity Framework our columns for the Values table that we will create.

namespace ACMEBank.API.Models
{
    public class Value
    {
        public int Id { get; set; }
        public string Name { get; set; }
    }
}

Now create a folder in the root of the project call "Entities" and create a class call EntitiesContext

using ACMEBank.API.Models;
using Microsoft.EntityFrameworkCore;

namespace ACMEBank.API.Entities
{
    public class EntitiesContext : DbContext
    {
        public EntitiesContext(DbContextOptions options) : base(options){}

        public DbSet Values {get;set;}


    }
}

Finally, we are ready to make our last code change, open the Startup.cs file and add the following line to the ConfigureServices method

services.AddDbContext(x => x.UseMySql(Configuration.GetConnectionString("DefaultConnection")));

The completed code should look like the following

        public void ConfigureServices(IServiceCollection services)

        {

            services.AddDbContext(x => x.UseMySql(Configuration.GetConnectionString("DefaultConnection")));

            services.AddControllers();

        }")));

So the code ties together to make our first migration, the Value class used for the columns in the database, the DbSet in EntitiesContext class represents the tables. Finally, the Startup code, tells Asp.Net Core that the database provider is MySQL, and it also injects the connection string into the EntitiesContext instance when it's created.  We now have all the parts we need to create our acmebank database.  All we need to do now is run the .NET Core Entity Framework Core tool in the command line.

Open a terminal session in Visual Studio, and go into the ACMEBank.API root folder.  We are going to install the Entity Framework tools in the .NET Core CLI.  Type the following command in the terminal dotnet tool install --global dotnet-ef

Now run the migration command to execute our Entity Framework code by typing dotnet ef migrations add InitialDbCreate

You've just created a database from scratch using Entity Framework Core

Your folder structure should look like the following when completed