Getting Started with EF Core

In this tutorial, you create a .NET Core console app that performs data access against a SQLite database using Entity Framework Core.

You can follow the tutorial by using Visual Studio on Windows, or by using the .NET CLI on Windows, macOS, or Linux.

View this article's sample on GitHub.

Install the following software:

dotnet new console -o EFGetStarted
cd EFGetStarted

To install EF Core, you install the package for the EF Core database provider(s) you want to target. This tutorial uses SQLite because it runs on all platforms that .NET supports. For a list of available providers, see Database Providers.

dotnet add package Microsoft.EntityFrameworkCore.Sqlite

Define a context class and entity classes that make up the model.

using Microsoft.EntityFrameworkCore;
using System;
using System.Collections.Generic;

public class BloggingContext : DbContext
{
    public DbSet<Blog> Blogs { get; set; }
    public DbSet<Post> Posts { get; set; }

    public string DbPath { get; }

    public BloggingContext()
    {
        var folder = Environment.SpecialFolder.LocalApplicationData;
        var path = Environment.GetFolderPath(folder);
        DbPath = System.IO.Path.Join(path, "blogging.db");
    }

    // The following configures EF to create a Sqlite database file in the
    // special "local" folder for your platform.
    protected override void OnConfiguring(DbContextOptionsBuilder options)
        => options.UseSqlite($"Data Source={DbPath}");
}

public class Blog
{
    public int BlogId { get; set; }
    public string Url { get; set; }

    public List<Post> Posts { get; } = new();
}

public class Post
{
    public int PostId { get; set; }
    public string Title { get; set; }
    public string Content { get; set; }

    public int BlogId { get; set; }
    public Blog Blog { get; set; }
}

EF Core can also reverse engineer a model from an existing database.

Tip: This application intentionally keeps things simple for clarity. Connection strings should not be stored in the code for production applications. You may also want to split each C# class into its own file.

The following steps use migrations to create a database.

• Open Program.cs and replace the contents with the following code:

  using System;
  using System.Linq;
  using Microsoft.EntityFrameworkCore;
  
  using var db = new BloggingContext();
  
  // Note: This sample requires the database to be created before running.
  Console.WriteLine($"Database path: {db.DbPath}.");
  
  // Create
  Console.WriteLine("Inserting a new blog");
  db.Add(new Blog { Url = "http://blogs.msdn.com/adonet" });
  await db.SaveChangesAsync();
  
  // Read
  Console.WriteLine("Querying for a blog");
  var blog = await db.Blogs
      .OrderBy(b => b.BlogId)
      .FirstAsync();
  
  // Update
  Console.WriteLine("Updating the blog and adding a post");
  blog.Url = "https://devblogs.microsoft.com/dotnet";
  blog.Posts.Add(
      new Post { Title = "Hello World", Content = "I wrote an app using EF Core!" });
  await db.SaveChangesAsync();
  
  // Delete
  Console.WriteLine("Delete the blog");
  db.Remove(blog);
  await db.SaveChangesAsync();
  

dotnet run

• Follow the ASP.NET Core Tutorial to use EF Core in a web app
• Learn more about LINQ query expressions
• Configure your model to specify things like required and maximum length
• Use Migrations to update the database schema after changing your model