ErsatzTV/ErsatzTV.Infrastructure/Data/Configurations/Collection/CollectionConfiguration.cs

using ErsatzTV.Core.Domain;
using Microsoft.EntityFrameworkCore;
using Microsoft.EntityFrameworkCore.Metadata.Builders;

namespace ErsatzTV.Infrastructure.Data.Configurations
{
    public class CollectionConfiguration : IEntityTypeConfiguration<Collection>
    {
        public void Configure(EntityTypeBuilder<Collection> builder)
        {
            builder.ToTable("Collection");

            builder.HasMany(c => c.MediaItems)
                .WithMany(m => m.Collections)
                .UsingEntity<CollectionItem>(
                    j => j.HasOne(ci => ci.MediaItem)
                        .WithMany(mi => mi.CollectionItems)
                        .HasForeignKey(ci => ci.MediaItemId)
                        .OnDelete(DeleteBehavior.Cascade),
                    j => j.HasOne(ci => ci.Collection)
                        .WithMany(c => c.CollectionItems)
                        .HasForeignKey(ci => ci.CollectionId)
                        .OnDelete(DeleteBehavior.Cascade),
                    j => j.HasKey(ci => new { ci.CollectionId, ci.MediaItemId }));
        }
    }
}