Laravel select models based on relationship - php

Question

I am working on a library application and I want to create a function where the user can rent out a book to a customer. However, I want the books that are rented out right now to not show up in the select box when renting out another book.
I have looked up several articles about this, but couldn't really make up a solution so I would be happy about any help.
The idea is, that when a book has the attribute "maxreturndate" set it won't show up.
CheckedOutController:
<?php
namespace App\Http\Controllers;
use Illuminate\Http\Request;
use App\CheckedOut;
use App\Book;
use App\Reader;
class CheckedOutController extends Controller
{
/**
* Display a listing of the resource.
*
* #return \Illuminate\Http\Response
*/
public function index()
{
$checkedOuts = CheckedOut::with(['book', 'reader'])->get();
return view('checkedouts/index', compact('checkedOuts'));
}
/**
* Show the form for creating a new resource.
*
* #return \Illuminate\Http\Response
*/
public function create()
{
$books = Book::all();
$readers = Reader::all();
return view('checkedouts/create', compact('books','readers'));
}
/**
* Store a newly created resource in storage.
*
* #param \Illuminate\Http\Request $request
* #return \Illuminate\Http\Response
*/
public function store(Request $request)
{
$validatedData = $request->validate([
'book_id' => 'required',
'reader_id' => 'required',
'maxreturndate' => 'required|date',
'returndate' => 'nullable',
]);
$checkedOut = CheckedOut::create($validatedData);
return redirect('checkedouts')->with('success', 'Buch wurde erfolgreich verliehen!');
}
/**
* Display the specified resource.
*
* #param int $id
* #return \Illuminate\Http\Response
*/
public function show($id)
{
//
}
/**
* Show the form for editing the specified resource.
*
* #param int $id
* #return \Illuminate\Http\Response
*/
public function edit($id)
{
//
}
/**
* Update the specified resource in storage.
*
* #param \Illuminate\Http\Request $request
* #param int $id
* #return \Illuminate\Http\Response
*/
public function update(Request $request, $id)
{
//
}
/**
* Remove the specified resource from storage.
*
* #param int $id
* #return \Illuminate\Http\Response
*/
public function destroy($id)
{
//
}
}
index.blade.php
#extends('layout')
#section('title')
<title>Alle ausgeliehen Bücher</title>
#section('content')
<style>
.uper {
margin-top: 40px;
}
</style>
<div class="uper">
#if(session()->get('success'))
<div class="alert alert-success">
{{ session()->get('success') }}
</div><br />
#endif
<table class="table table-hover">
<thead>
<tr>
<td>ID</td>
<td>Titel</td>
<td>Verliehen an</td>
<td>Verleihdatum</td>
<td>Fällig am</td>
<td>Zurückgebracht am</td>
<td colspan="2">Funktionen</td>
</tr>
</thead>
<tbody>
#foreach($checkedOuts as $checkedOut)
<tr>
<td>{{$checkedOut->id}}</td>
<td>{{$checkedOut->book->title}}</td>
<td>{{$checkedOut->reader->name}}</td>
<td>{{$checkedOut->created_at}}</td>
<td >{{$checkedOut->maxreturndate}}</td>
<td>{{$checkedOut->returndate}}</td>
<td></td>
<td>Bearbeiten</td>
<td>Anzeigen</td>
<td>
<form action="{{ route('checkedouts.destroy', $checkedOut->id)}}" method="post">
#csrf
#method('DELETE')
<button class="btn btn-danger" type="submit">Löschen</button>
</form>
</td>
</tr>
#endforeach
</tbody>
</table>
<div>
#endsection
Migrations:
<?php
use Illuminate\Database\Migrations\Migration;
use Illuminate\Database\Schema\Blueprint;
use Illuminate\Support\Facades\Schema;
class CreateCheckedOutsTable extends Migration
{
/**
* Run the migrations.
*
* #return void
*/
public function up()
{
Schema::create('checked_outs', function (Blueprint $table) {
$table->bigIncrements('id');
$table->bigInteger('book_id')->unsigned();
$table->foreign('book_id')->references('id')->on('books')->onDelete('cascade');
$table->bigInteger('reader_id')->unsigned();
$table->foreign('reader_id')->references('id')->on('readers')->onDelete('cascade');
$table->date('maxreturndate');
$table->date('returndate')->nullable();
$table->timestamps();
});
}
/**
* Reverse the migrations.
*
* #return void
*/
public function down()
{
Schema::dropIfExists('checked_outs');
}
}
create.blade.php
#extends('layout')
#section('title')
<title>Buch verleihen</title>
#section('stylesheets')
<script src="http://code.jquery.com/jquery-3.4.1.min.js"></script>
<script src="https://cdn.jsdelivr.net/npm/select2#4.0.13/dist/js/select2.min.js"></script>
<link href="https://cdn.jsdelivr.net/npm/select2#4.0.13/dist/css/select2.min.css" rel="stylesheet" />
#endsection
#section('content')
<style>
.uper {
margin-top: 40px;
}
</style>
<div class="card uper">
<div class="card-header">
Buch verleihen
</div>
<div class="card-body">
<form method="post" action="{{ route('checkedouts.store') }}">
<div class="form-group">
#csrf
<label for="book_id">Buch:</label>
<select name="book_id" class="form-control select2-single <!-- #error('book_id') is-invalid #enderror -->">
#foreach ($books as $book)
<option value="{{ $book->id }}">{{ $book->title }}</option>
#endforeach
</select>
#error('book_id')
<div class="alert alert-danger">{{ $message }}</div>
#enderror
</div>
<div class="form-group">
<label for="reader_id">Verleihen an:</label>
<select name="reader_id" class="form-control select2-single <!-- #error('reader_id') is-invalid #enderror -->">
#foreach ($readers as $reader)
<option value="{{ $reader->id }}">{{ $reader->name }}</option>
#endforeach
</select>
#error('reader_id')
<div class="alert alert-danger">{{ $message }}</div>
#enderror
</div>
<div class="form-group">
<label for="maxreturndate">Zurückbringen bis:</label>
<input type="date" class="form-control" name="maxreturndate" />
#error('name')
<div class="alert alert-danger">{{ $message }}</div>
#enderror
</div>
<button type="submit" class="btn btn-primary">Verleihen</button>
</form>
</div>
</div>
<script type="text/javascript">
$(".select2-single").select2();
</script>
#endsection
The relationship between the 3 Models:
Book:
public function checkedOut(){
return $this->hasOne(CheckedOut::class);
}
Reader:
public function checkedOut()
{
return $this->belongsTo(CheckedOut::class);
}
CheckedOut:
public function book(){
return $this->belongsTo(Book::class);
}
public function reader(){
return $this->belongsTo(Reader::class);
}

Answer 1

My suggestion is to set up Books and Readers with a many-to-many relationship. Now, your models could look like this:
<?php
namespace App;
use Illuminate\Database\Eloquent\Model;
use Illuminate\Database\Eloquent\Relations\Pivot;
class Book extends Model
{
public function readers()
{
return $this
->belongsToMany(\App\Reader::class, 'checked_outs')
->using(\App\Checkout::class)
->withPivot(['returndate', 'maxreturndate']);
}
}
class Reader extends Model
{
public function books()
{
return $this
->belongsToMany(\App\Book::class, 'checked_outs')
->using(\App\Checkout::class)
->withPivot(['returndate', 'maxreturndate']);
}
}
class Checkout extends Pivot
{
// this should be named `book_reader` but we override it here
$table = "checked_outs";
$dates = [
"maxreturndate",
"returndate",
];
}
I have created a pivot model which isn't necessary, but allows you to operate directly on the pivot table and cast the extra attributes to dates automatically. Whether this is useful is a matter of opinion. You should rename the checked_outs table to book_reader which is the naming convention that Laravel expects for a pivot table.
Getting the books that aren't checked out is simple enough to do as follows, using the doesntHave method to check for absence of a relationship.
public function create()
{
$books = Book::doesntHave("readers")->get();
$readers = Reader::all();
return view('checkedouts/create', compact('books','readers'));
}
And "checking out" a book could look like this:
public function store(Request $request)
{
$reader = Reader::find($request->reader_id);
$reader
->books()
->attach(
$request->book_id,
["returndate" => Carbon\Carbon::now()->addDays(7)]
);
}

Answer 2

when a book has the attribute "maxreturndate" set it won't show up
Since you did not specify in your migration, I am going to assume here that you have a maxreturndate nullable field in your books table, then you should be able to simply create a local scope when you want your list of "not rented" books.
Here's an example on creating a notRented scope:
// in your Book model define the local scope
public function scopeNotRented($query){
return $query->whereNotNull('maxreturndate');
}
// in the create method of your controller
public function create()
{
$books = Book::notRented()->get();
$readers = Reader::all();
return view('checkedouts/create', compact('books','readers'));
}