Asp.Net Core Migration Commands Complete Guide

Step 1: Set Up Your ASP.NET Core Web Application

First, make sure you have .NET SDK installed on your system. You can create a new ASP.NET Core web application using the following command in your terminal or command prompt:

dotnet new mvc -n MyWebApp
cd MyWebApp

Step 2: Modify Program.cs (for .NET 6 and later) or Startup.cs (for .NET 5 and earlier)

In the newer versions of ASP.NET Core (like .NET 6 and later), configurations are typically done in Program.cs. If you're using an older version, some of these settings might be in Startup.cs as well.

Program.cs (For .NET 6 and Later)

Open Program.cs and inject a database context:

using Microsoft.EntityFrameworkCore;
using MyWebApp.Data;

var builder = WebApplication.CreateBuilder(args);

// Add services to the container.
builder.Services.AddControllersWithViews();

// Adding Entity Framework with SQLite database provider.
builder.Services.AddDbContext<ApplicationDbContext>(options =>
    options.UseSqlite(builder.Configuration.GetConnectionString("DefaultConnection")));

var app = builder.Build();

// Configure the HTTP request pipeline.
if (!app.Environment.IsDevelopment())
{
    app.UseExceptionHandler("/Home/Error");
    app.UseHsts();
}

app.UseHttpsRedirection();
app.UseStaticFiles();

app.UseRouting();

app.UseAuthorization();

app.MapControllerRoute(
    name: "default",
    pattern: "{controller=Home}/{action=Index}/{id?}");

app.Run();

Startup.cs (For .NET 5)

If you're using .NET 5, open Startup.cs, and modify the ConfigureServices method:

public void ConfigureServices(IServiceCollection services)
{
    services.AddControllersWithViews();

    // Adding Entity Framework with SQLite database provider.
    services.AddDbContext<ApplicationDbContext>(options =>
        options.UseSqlite(Configuration.GetConnectionString("DefaultConnection")));
}

Add a connection string to appsettings.json:

"ConnectionStrings": {
    "DefaultConnection": "Data Source=MyWebApp.db"
}

Step 3: Create a Database Context Class

Create a new file named ApplicationDbContext.cs inside a folder called Data.

using Microsoft.EntityFrameworkCore;

namespace MyWebApp.Data
{
    public class ApplicationDbContext : DbContext
    {
        public ApplicationDbContext(DbContextOptions<ApplicationDbContext> options)
            : base(options)
        {
        }

        public DbSet<Product> Products { get; set; }
    }

    public class Product
    {
        public int Id { get; set; }
        public string Name { get; set; }
        public decimal Price { get; set; }
    }
}

Step 4: Install Entity Framework Core Tools

Make sure that the Entity Framework Core tools are available. You can install them globally via NuGet package manager with the following command:

dotnet tool install --global dotnet-ef

Alternatively, you can add them as a development-time dependency in your MyWebApp.csproj file:

<ItemGroup>
    <DotNetCliToolReference Include="Microsoft.EntityFrameworkCore.Tools" Version="6.0.1" />
</ItemGroup>

After adding the DotNetCliToolReference, run the following command to restore packages:

dotnet restore

Step 5: Add a Migration

Now that you've defined your data models, you need to create an initial migration. Run the following command in your terminal or command prompt:

dotnet ef migrations add InitialCreate

This will scaffold a migration file in the Migrations folder in your project under a folder like YourMigrationName.

The migration 'InitialCreate' has been created in directory 'Migrations\20230915000000_InitialCreate'.

Step 6: Update the Database

To apply this migration to your database, run the following command:

dotnet ef database update

This command will create a SQLite database file (MyWebApp.db) in your project root and apply the migration commands to it, setting up the necessary tables.

Done.

Step 7: Check the Migrations

You can list all migrations that have been applied or are pending using the following command:

dotnet ef migrations list

This command will display a list of all migrations with their status (applied or not).

Step 8: Remove a Migration (Optional)

If you need to remove the last migration (for example, if you made a mistake), you can do so with the following command:

dotnet ef migrations remove

This will undo the last migration, removing the corresponding migration class file from the Migrations folder.

Step 9: Rollback to a Specific Migration (Optional)

If you want to rollback the current migration history to a specific point, use the following command:

dotnet ef database update [previous_migration_name]

Replace [previous_migration_name] with the name of the migration to which you want to roll back. For instance:

dotnet ef database update InitialCreate

Step 10: Drop the Database (Optional)

If you need to completely delete your database, you can use this command:

dotnet ef database drop

This command will delete the MyWebApp.db file from your project.

Wrap Up

By following these steps, you should now have a basic understanding of how to work with ASP.NET Core migration commands. You can always reference the official Entity Framework Core documentation for more detailed and advanced usage scenarios.