DreamsCaster/DreamsCaster/AppDbContext.cs

using System.ComponentModel.DataAnnotations.Schema;
using DreamsCaster.Models;
using Microsoft.EntityFrameworkCore;
using Console = DreamsCaster.Models.Console;

namespace DreamsCaster;

public class AppDbContext : DbContext
{
	public DbSet<Game> Games { get; set; }
	public DbSet<Console> Consoles { get; set; }

	public DbSet<Developer> Developers { get; set; }
	public DbSet<Publisher> Publishers { get; set; }
	public DbSet<Manufacturer> Manufacturers { get; set; }
	public DbSet<Release> Releases { get; set; }

	public DbSet<MetaData<Game>> GamesMetaData { get; set; }
	public DbSet<MetaData<Console>> ConsolesMetaData { get; set; }
	public DbSet<MetaData<Developer>> DevelopersMetaData { get; set; }
	public DbSet<MetaData<Publisher>> PublishersMetaData { get; set; }
	public DbSet<MetaData<Manufacturer>> ManufacturersMetaData { get; set; }

	public AppDbContext() : base() { }

	public AppDbContext(DbContextOptions<AppDbContext> options) : base(options) { }

	protected override void OnModelCreating(ModelBuilder modelBuilder)
	{
		base.OnModelCreating(modelBuilder);

		ConfigureMetaDataFor<Console>(modelBuilder);
		ConfigureMetaDataFor<Game>(modelBuilder);
		ConfigureMetaDataFor<Publisher>(modelBuilder);
		ConfigureMetaDataFor<Developer>(modelBuilder);
		ConfigureMetaDataFor<Manufacturer>(modelBuilder);
	}

	void ConfigureMetaDataFor<T>(ModelBuilder modelBuilder) where T : MetaDataContainer<T>
	{
		modelBuilder.Entity<T>()
			.HasOne(a => a.Data)
			.WithOne(b => b.Owner)
			.HasForeignKey<MetaData<T>>(c => c.OwnerId)
			.OnDelete(DeleteBehavior.Cascade);
	}
}

public static class DatabaseExtensions
{
	public static bool TryGet<T>(this IEnumerable<T> haystack, Guid id, out T val) where T : IdEntity
	{
		if (haystack.Select(hay => hay.Id).Contains(id))
		{
			val = haystack.FirstOrDefault(hay => hay.Id.Equals(id));
			return true;
		}

		val = null;
		return false;
	}
}