DataContext.cs

namespace CascadeDelete.Models
{
    public class DataContext: DbContext
    {
        public virtual DbSet<Resident> Residents { get; set; }
        public virtual DbSet<City> Cities { get; set; }
        public virtual DbSet<ResidentCityOwn> ResidentCityOwn { get; set; }

        protected override void OnModelCreating(DbModelBuilder modelBuilder)
        {
            // Fluent API configurations
            modelBuilder.Entity<Resident>()
                .HasRequired(e => e.City)
                .WithMany(e => e.Residents)
                .WillCascadeOnDelete(false);
        }
    }
}