Laravel add condition inside model public function relation - php

Question

I am developing a booking system which used Laravel 7.0
so in this system I created a table called 'bookings'
and I created its model called Booking.php
inside this Booking.php I put in relation function to join its model to transaction table like below
public function transaction()
{
return $this->belongsTo('App\Models\Transaction', 'id', 'booking_id');
}
suddenly a new requirement coming in, and this booking will have its child
so to differentiate between the booking parent and its child i am adding a new column to the booking table called
'parent_booking_id'
I don't want to change the code function too much so I am thinking on making condition to make sure the relation of the booking points to the correct transaction
I am thinking of code like this to be written
public function transaction()
{
return $this->belongsTo('App\Models\Transaction', 'parent_booking_id' ?? 'id', 'booking_id');
}
but it is not working as intended
the logic is
If the parent_booking_id exists then join the 'booking_id' column at table transaction to 'parent_booking_id' column at table bookings
else
it will join the 'booking_id' column at table transaction to 'id' column at table bookings

Answer 1

I am not really sure if I understood everything.
I not using that kind of logic inside models, but if you really want it. I'm not sure, but I think this could work.
public function parent_booking()
{
$this->belongsTo('App\Models\Booking', 'parent_booking_id');
}
public function transaction()
{
if ($this->has('parent_booking')) {
return $this->hasOne('App\Models\Transaction', 'parent_booking_id', 'booking_id');
} else {
return $this->hasOne('App\Models\Transaction', 'booking_id');
}
}
If ywhat you try to achieve is this:
When a booking have a parent_booking, attach the transaction to the parent_booking, else, attach it to the booking.
To do this, my suggestion is to do things more like this.
public function parent_booking()
{
$this->belongsTo('App\Models\Booking', 'parent_booking_id');
}
public function childs_booking()
{
$this->hasMany('App\Models\Booking', 'parent_booking_id');
}
Then, you can do this in controller:
$booking = Booking::with('parent_booking')->find($id);
if ($booking->has('parent_booking')) {
//do some stuff.
$booking->parent_booking->transaction->associate($transaction->id);
} else {
//do other stuff
$booking->transaction->associate($transaction->id);
}
And for sure, you will want to retrieve the right transaction. There is an example on a retrieve of every bookings.
$bookings = Booking::with(array('parent_booking', function($query) {
return $query->with('transaction');
}))->with('transaction')->get();
foreach($bookings as $booking) {
if ($booking->has('parent_booking')) {
$transaction_to_use = $booking->parent_booking->transaction;
} else {
$transaction_to_use = $booking->transaction;
}
}
You can also perform something like this:
$transactions = Transaction::with(array('booking', function($query) {
return $query->with('childs_booking');
}))->get();
This way you get every transactions with their booking. You also have every child booking.

Answer 2

Finally found the solution to this problem
the proper way to fix this is by
making 2 relation
and then altering code using where condition to make sure it pass the correct relation based on booking value
BUT because this way of fixing require to much code changes i try to find other ways
and the other ways is to instead of creating 'parent_booking_id' i create a column called 'primary_booking_id'
this 'primary_booking_id' will always contain the booking_id of the first booking being made
so on first time create the model I will update so that it gains the booking_id
$booking->update(['primary_booking_id' => $booking->id]);
and then during creation of its child I will put into the primary_booking_id into the creation
$input['primary_booking_id'] => $previous_booking->primary_booking_id;
$booking::create($input);
so the way this is handled require to make just minor changes to booking transaction relation function as below
public function transaction()
{
return $this->hasOne('App\Models\Transaction', 'booking_id', 'primary_booking_id');
}
voila!
it works and no major changes involve