Enums in EF Core

EFCoreEnums.csproj

<Project Sdk="Microsoft.NET.Sdk">

  <PropertyGroup>
    <OutputType>Exe</OutputType>
    <TargetFramework>netcoreapp2.2</TargetFramework>
    <RootNamespace>EFCoreEnums</RootNamespace>
  </PropertyGroup>

  <ItemGroup>
    <PackageReference Include="Microsoft.EntityFrameworkCore.Design" Version="2.2.6" />
    <PackageReference Include="Microsoft.EntityFrameworkCore.Sqlite" Version="2.2.6" />
  </ItemGroup>

</Project>

Program.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading.Tasks;
using Microsoft.EntityFrameworkCore;

namespace EFCoreEnums
{
    public class Wine
    {
        public int WineId { get; set; }
        public string Name { get; set; }

        public WineVariantId WineVariantId { get; set; }
        public WineVariant WineVariant { get; set; }
    }

    public enum WineVariantId : int
    {
        Red,
        White,
        Rose
    }

    public class WineVariant
    {
        public WineVariantId WineVariantId { get; set; }
        public string Name { get; set; }

        public List<Wine> Wines { get; set; }
    }

    public class WineContext : DbContext
    {
        public DbSet<Wine> Wines { get; set; }
        public DbSet<WineVariant> WineVariants { get; set; }

        protected override void OnConfiguring(DbContextOptionsBuilder optionsBuilder)
        {
            optionsBuilder.UseSqlite("Data Source=wines.db");
        }

        protected override void OnModelCreating(ModelBuilder modelBuilder)
        {
            modelBuilder
                .Entity<Wine>()
                .Property(e => e.WineVariantId)
                .HasConversion<int>();

            modelBuilder
                .Entity<WineVariant>()
                .Property(e => e.WineVariantId)
                .HasConversion<int>();

            modelBuilder
                .Entity<WineVariant>().HasData(
                    Enum.GetValues(typeof(WineVariantId))
                        .Cast<WineVariantId>()
                        .Select(e => new WineVariant()
                        {
                            WineVariantId = e,
                            Name = e.ToString()
                        })
                );
        }
    }

    public static class Program
    {
        public static async Task Main(string[] args)
        {
            using (var db = new WineContext())
            {
                await db.Database.MigrateAsync();

                db.Wines.Add(new Wine
                {
                    Name = "Gutturnio",
                    WineVariantId = WineVariantId.Red,
                });

                db.Wines.Add(new Wine
                {
                    Name = "Ortrugo",
                    WineVariantId = WineVariantId.White,
                });

                await db.SaveChangesAsync();
            }

            using (var db = new WineContext())
            {
                var gutturnio = await db.Wines
                    .AsNoTracking()
                    .Include(w => w.WineVariant)
                    .FirstAsync(w => w.Name == "Gutturnio");
                
                Console.WriteLine($"{gutturnio.Name} is a {gutturnio.WineVariant.Name} wine");
            }
        }
    }
}

Hi @rich0726, that would be a many to many relationship, take a look at here: https://docs.microsoft.com/en-us/ef/core/modeling/relationships?tabs=fluent-api%2Cfluent-api-simple-key%2Csimple-key#many-to-many

What changes would we have to do to this, if we need it as a many-to-many relationship, then convert it back to a ICollection of enum(or class with enum as Id)

It should be updated a bit as here: https://gist.github.com/Sergio1C/1f08c203011d42c4fcf7a7e43ff590a5/revisions