Laravel: avoid duplicate entries in database [duplicate] - php

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Laravel avoid duplicate entry from model
(2 answers)
Closed 3 years ago.
I'm building a Laravel API. I have a models called Reservations. I want to avoid that a user creates two reservations for the same product and time period.
I have the following:
$reservation = Reservation::firstOrCreate([
'listing_id' => $request->listing_id,
'user_id_from' => $request->user_id_from,
'start_date' => $request->start_date,
'end_date' => $request->end_date,
]);
return new ReservationResource($reservation);
Documentation says:
The firstOrCreate method will attempt to locate a database record
using the given column / value pairs
The above code is working:
it does add the item to the database if it does not exist yet (in
this case, the reply to the REST API returns the new model instance
which is correct.
it does not add the item to the database if the combination equals listing_id, user_id_from, start_date and end_date.
However, in the latter case (item already exists), it will also return in the REST API reply a reservation with the ID of the matched row.
Example: in the below table, reservation with id 2 already exists:
id listing_id user_id_from start_date end_date
------------------------------------------------------
1 2 3 2019-09-12 2019-10-14
Sending the below REST API request:
{
"listing_id": 2,
"user_id_from": 3,
"start_date": "2019-09-12",
"end_date": "2019-10-14",
}
returns
"data": {
"id": 1,
"user_id_from": 3,
"listing_id": 2,
"price": 388,
"start_date": "2019-09-12",
"end_date": "2019-10-14",
}
I would want to have a JSON reply stating that the item already exists. How can this be achieved?

Answer 1

firstOrCreate() is just a two-part function as you might expect, doing a lookup on first() and falling back to create() if not exists. You could implement much the same logic in your controller, and append a message to the first() result if it exists, and return the result as-is if created. Alternatively, you could modify the response with a HTTP_OK or HTTP_CREATED depending on the result. Or both.
public function store(Request $request)
{
$attributes = [
'listing_id' => $request->input('listing_id'),
'user_id_from' => $request->input('user_id_from'),
'start_date' => $request->input('start_date'),
'end_date' => $request->input('end_date')
];
// return existing reservation if exists
$reservation = Reservation::where($attributes)->first();
if ($reservation !== null) {
// add explicit message here if you want
return response(json_encode($reservation), Response::HTTP_OK);
}
// else create a new one
$reservation = Reservation::create($attributes);
// reload model
$reservation = Reservation::find($reservation->id);
return response(json_encode($reservation), Response::HTTP_CREATED);
}

Answer 2

I think you are looking for Laravel's wasRecentlyCreated:
if(! $reservation->wasRecentlyCreated){
// create & encode a JSON response or use this variable & method on the blade page
}