Entity Framework

This document describes how to use Entity Framework Core, an ORM library for C# with YugabyteDB.

Prerequisites

Before you start using Entity framework:

Install YugabyteDB 2.6 or later and start a single node local cluster. Refer YugabyteDB Quick Start Guide to install and start a local cluster.
Install .NET Core SDK 6.0 or later.

Use Entity Framework

You can start using Entity Framework with YugabyteDB as follows:

Create a new dotnet project with the command:

dotnet new console -o EFGetStarted && cd EFGetStarted

Install Entity Framework Core by installing the package for the database provider(s) you want to target. In this case, it is Entity Framework PostgreSQL.

dotnet add package Npgsql.EntityFrameworkCore.PostgreSQL

Create a model from the existing database in a Model.cs file using an editor and add the following code:

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

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

        protected override void OnConfiguring(DbContextOptionsBuilder optionsBuilder)
            => optionsBuilder.UseNpgsql("Host=localhost;Port=5433;Database=yugabyte;Username=yugabyte;Password=yugabyte");
    }

    public class Blog
    {
        public int BlogId { get; set; }
        public string Url { get; set; }
        public List<Post> Posts { get; set; }
    }

    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; }
    }
}

Configure the database properties accordingly. The default user and password for YugabyteDB is yugabyte, and the default port is 5433.

Use EF Migrations to create a database from the model.

dotnet tool install --global dotnet-ef
dotnet add package Microsoft.EntityFrameworkCore.Design --version 6.0.0 //Mention the .NET Core SDK version you installed above.
dotnet ef migrations add InitialCreate
dotnet ef database update

Perform the CRUD operations after the database is created. Replace the code in Program.cs file under the EFGetStarted project with the following:

using System;
using System.Linq;

namespace ConsoleApp.PostgreSQL
{
    internal class Program
    {
        private static void Main()
        {
            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.abc.com/adonet" });
                db.SaveChanges();

                // Read
                Console.WriteLine("Querying for a blog");
                var blog = db.Blogs
                    .OrderBy(b => b.BlogId)
                    .First();
                Console.WriteLine("ID :" + blog.BlogId + "\nURL:" + blog.Url);

                // Delete
                Console.WriteLine("Deleting the blog");
                db.Remove(blog);
                db.SaveChanges();
            }
        }
    }
}

Run the application and verify the results.

dotnet run

Inserting a new blog
Querying for a blog
ID :1
URL:http://blogs.abc.com/adonet
Deleting the blog