using System;

using System.Collections.Generic;

using System.IO;

using System.Linq;

using Microsoft.EntityFrameworkCore;

​

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 = Path.Join(path, "blogging.db");

        DbPath = ":memory:";

    }

​

    // 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}", x => x.UseNetTopologySuite());

}

​

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; }

}

public class Program

{

    public static void Main()

    {

        using var db = new BloggingContext();

        db.Database.OpenConnection();

        db.Database.EnsureCreated();

​

        // 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" });

        db.SaveChanges();

​

        // Read

        Console.WriteLine("Querying for a blog");

        var blog = db.Blogs

            .OrderBy(b => b.BlogId)

            .First();

​

        // 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!" });

        db.SaveChanges();

​

        // Delete

        Console.WriteLine("Delete the blog");

        db.Remove(blog);

        db.SaveChanges();

    }

}