Booking system with many to many laravel relationship - php

Question

I'm trying to make an app where airbnb hosts can have a log of their bookings, I created three models: Home, Guest and Booking. Booking being the main player, I also think there should be a pivot table but I'm not sure which models should it link... I decided to go with booking_guest but I'm getting the following error when I create a booking:
SQLSTATE[23000]: Integrity constraint violation: 1048 Column 'booking_id' cannot be null (SQL: insert into `booking_guest` (`booking_id`, `guest_id`) values (?, 1), (?, 2))
I do something like this in my BookingController:
public function create(Request $request)
{
$guestIds = Guest::latest()->take(2)->pluck('id');
$home = Home::findOrFail(1);
$booking = new Booking();
$booking->home_id = $home->id;
$booking->guests()->attach($guestIds);
$booking->save();
return response()->json([
'booking' => $booking,
]);
}
I'm not feeling too sure about this configuration, could you guys share some light on me.
These are my models:
class Home extends Model
{
public function guests()
{
return $this->belongsToMany('App\Models\Guest', 'guest_home', 'home_id', 'guest_id');
}
public function bookings()
{
return $this->hasMany('App\Models\Booking');
}
}
class Booking extends Model
{
public function guests()
{
return $this->belongsToMany('App\Models\Guest', 'booking_guest', 'booking_id', 'guest_id');
}
}
class Guest extends Model
{
public function bookings()
{
return $this->belongsToMany('App\Models\Booking', 'booking_guest', 'guest_id', 'booking_id');
}
}
My migrations:
//Booking guest pivot table
Schema::create('booking_guest', function (Blueprint $table) {
$table->increments('id');
$table->unsignedInteger('booking_id')->index();
$table->foreign('booking_id')->references('id')->on('bookings')->onDelete('cascade')->onUpdate('cascade');
$table->unsignedInteger('guest_id')->nullable()->index();
$table->foreign('guest_id')->references('id')->on('guests')->onDelete('cascade')->onUpdate('cascade');
$table->timestamps();
});
Schema::create('guests', function (Blueprint $table) {
$table->increments('id');
$table->string('fullName');
$table->text('country');
$table->timestamps();
});
Schema::create('bookings', function (Blueprint $table) {
$table->increments('id');
$table->unsignedInteger('home_id')->index();
$table->foreign('home_id')->references('id')->on('homes')->onDelete('cascade')->onUpdate('cascade');
$table->timestamp('entryDate')->nullable();
$table->timestamp('exitDate')->nullable();
$table->timestamps();
});
Schema::create('homes', function (Blueprint $table) {
$table->increments('id');
$table->unsignedInteger('host_id')->index();
$table->foreign('host_id')->references('id')->on('hosts')->onDelete('cascade')->onUpdate('cascade');
$table->string('fullAddress')->unique();
$table->integer('rooms')->unique();
$table->timestamps();
});

Answer 1

As you can see from here:
public function create(Request $request)
{
...
$booking = new Booking(); // <-- here
$booking->guests()->attach($guestIds); // <-- here
$booking->save(); // <-- here
...
}
you are creating a new instance of Booking, then associating to it a Guest and then saving the instance of Booking.
However ->attach(...) tries to associate the Booking with the Guest, but the Booking does not exists at that time on the DB.
I would suggest to use Booking::create, so that after that statement, the booking exists on the DB and so you can attach to it the Guest:
public function create(Request $request)
{
$guestIds = Guest::latest()->take(2)->pluck('id');
$home = Home::findOrFail(1);
$booking = Booking::create([ // <- using Booking::create
'home_id' => $home->id // <- using Booking::create
]); // <- using Booking::create
$booking->guests()->attach($guestIds);
return response()->json([
'booking' => $booking,
]);
}