C#•3y ago

How to keep track of third property in Many-To-Many

I have 2 models one that is Reservation and one that is Menu, They have a many-to-many relation but I wanna keep track on the reservation how many times one menu is ordered for that resrevation. This is my current many-to-many table :

        public int ReservationId { get; set; }
        public Reservation Reservation { get; set; }

        public int MenuId { get; set; }
        public int TimesOrdered { get; set; } <-- this property needs to keep track of how many times a menu has been ordered.
        public Menu Menu { get; set; }

        public int ReservationId { get; set; }
        public Reservation Reservation { get; set; }

        public int MenuId { get; set; }
        public int TimesOrdered { get; set; } <-- this property needs to keep track of how many times a menu has been ordered.
        public Menu Menu { get; set; }

This is my current OnModelCreating for that table

        modelBuilder.Entity<Reservation>()
            .HasMany(x => x.Menus)
            .WithMany(x => x.Reservations)
            .UsingEntity<ReservationMenu>(
                rm => rm.HasOne(x => x.Menu).WithMany().HasForeignKey(k => k.MenuId),
                rm => rm.HasOne(x => x.Reservation).WithMany().HasForeignKey(k => k.ReservationId),
                rm =>
                {
                    rm.HasKey(p => new { p.MenuId, p.ReservationId });
                }
            );

        modelBuilder.Entity<Reservation>()
            .HasMany(x => x.Menus)
            .WithMany(x => x.Reservations)
            .UsingEntity<ReservationMenu>(
                rm => rm.HasOne(x => x.Menu).WithMany().HasForeignKey(k => k.MenuId),
                rm => rm.HasOne(x => x.Reservation).WithMany().HasForeignKey(k => k.ReservationId),
                rm =>
                {
                    rm.HasKey(p => new { p.MenuId, p.ReservationId });
                }
            );

I am kinda stuck on how to approach this.

2 Replies

undisputed world champions•3y ago

why do you want to store this separately? cant you query it with something like _context.Menus.Count(m => m.Reservations.Any(r => r.Id == reservationId))?

LucifernoOP•3y ago

I could try that good point That worked!

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How to keep track of third property in Many-To-Many