How to display parent name in Laravel - php

Question

I have a departments table in db with id,name, and parent.The parent is the id that corresponds to the parent root.Now i have displayed the id(parent id) but i want to show the name of the department that correspond with this id.I have tried the query at the departmentcontroller ,index function but it gives me this error
Illuminate\Database\QueryException
SQLSTATE[42000]: Syntax error or access violation: 1066 Not unique table/alias: 'departments' (SQL: select departments.id, departments.parent, departments.name from departments inner join departments on department.id = departments.parent where id = parent)
DepartmentController.php
<?php
namespace App\Http\Controllers\Admin;
use App\Http\Controllers\Controller;
use Illuminate\Http\Request;
use App\Department;
use App\User;
use Illuminate\Support\Facades\DB;
class DepartmentController extends Controller
{
public function usersdep($id)
{
$department = Department::with('users')->find($id);
return view('admin.page-users')->with('users', $department->users);
}
public function treeView()
{
$departments = Department::with('childs')->where('parent', 0)->get();
return view('admin.page',compact('departments'));
}
public function index()
{
//$departments = \App\Department::all();
//return view('admin.department')->with('departments', $departments);
return $departments = DB::table('departments')
->join('departments', 'department.id', '=', 'departments.parent')
->select('departments.id','departments.parent','departments.name')->where('id','=','parent')->get();
}
department.blade.php
#extends ('layouts.master')
#section('title')
Department Management | Admin
#endsection
#section('content')
<div class="modal fade" id="exampleModal" tabindex="-1" role="dialog" aria-labelledby="exampleModalLabel" aria-hidden="true">
<div class="modal-dialog" role="document">
<div class="modal-content">
<div class="modal-header">
<h5 class="modal-title" id="exampleModalLabel">New department</h5>
<button type="button" class="close" data-dismiss="modal" aria-label="Close">
<span aria-hidden="true">×</span>
</button>
#if (session('status'))
<div class="alert alert-success" role="alert">
{{ session('status') }}
</div>
#endif
</div>
<form action="/save-department" method="POST">
{{ csrf_field() }}
<div class="modal-body">
<div class="form-group">
<label for="recipient-name" class="col-form-label">Name</label>
<input type="text" class="form-control" name="name" id="recipient-name">
</div>
<div class="form-group">
<label for="recipient-name" class="col-form-label">ID</label>
<input type="text" class="form-control" name="id" id="recipient-id">
</div>
<div class="form-group">
<label for="recipient-name exampleFormControlSelect2" class="col-form-label">Parent ID</label>
<input type="text" class="form-control" placeholder="Choose the department parent id"name="parent" id="recipient-parent">
<select multiple class="form-control" name="parent" id="recipient-parent">
#foreach($departments as $department)
<option>{{ $department->parent }}</option>
#endforeach
</select>
</div>
</div>
<div class="modal-footer">
<button type="button" class="btn btn-secondary" data-dismiss="modal">Close</button>
<button type="submit" class="btn btn-primary">Save</button>
</div>
</form>
</div>
</div>
</div>
<div class="row">
<div class="col-md-12">
<div class="card">
#if (session('status'))
<div class="alert alert-success" role="alert">
{{ session('status') }}
</div>
#endif
<div class="card-header">
<h4 class="card-title my-4 text-center font-weight-light"> Department Management </h4>
</div>
<div class="card-body">
<div class="table-responsive">
<table class="table">
<thead class=" text-primary">
<th>Department</th>
<button type="button" class="btn btn-primary float-right" data-toggle="modal" data-target="#exampleModal" >Add</button>
<thead class=" text-primary">
<th>ID</th>
<th>Name</th>
<th>Parent ID</th>
<th>Edit</th>
<th>Delete</th>
</thead>
</thead>
<tbody>
#foreach($departments as $department)
<tr>
<td>{{ $department->id }}</td>
<td>{{ $department->name }}</td>
<td>{{ $department->parent }}</td>
<td>
Edit
</td>
<td>
<form action="{{ url('department-delete/'.$department->id) }}" method="POST">
{{ csrf_field() }}
{{ method_field('DELETE') }}
<button type="submit" class="btn btn-danger">Delete</button>
</form>
</td>
</tr>
#endforeach
See the Departments and Employees
</tbody>
</table>
</div>
</div>
</div>
</div>
#endsection
#section('scripts')
#endsection
web.php
<?php
use App\User;
use App\Department;
use App\Events\WebsocketDemoEvent;
/*
|--------------------------------------------------------------------------
| Web Routes
|--------------------------------------------------------------------------
|
| Here is where you can register web routes for your application. These
| routes are loaded by the RouteServiceProvider within a group which
| contains the "web" middleware group. Now create something great!
|
*/
Route::get('/', function () {
broadcast(new WebsocketDemoEvent('some data'));
return view('welcome');
});
Route::get('/page', function () {
return view('admin.page');
});
Auth::routes();
Route::get('/home', 'HomeController#index')->name('home');
Route::group(['middleware' => ['auth','admin']], function () {
Route::get('/role-register','Admin\DashboardController#registered');
Route::delete('/role-delete/{id}', 'Admin\DashboardController#registerdelete');//delete user
Route::post('/save-user', 'Admin\DashboardController#store');
Route::get('/department', 'Admin\DepartmentController#index');
Route::post('/save-department', 'Admin\DepartmentController#store');
Route::get('/department-edit/{id}', 'Admin\DepartmentController#edit');//edit department
Route::put('/department-update/{id}', 'Admin\DepartmentController#update');
Route::delete('/department-delete/{id}', 'Admin\DepartmentController#delete');//delete department
Route::get('/page-users/{id}', 'Admin\DepartmentController#usersdep');//show users
});
Auth::routes();
Route::get('/home', 'HomeController#index')->name('home');
Route::get('/chats', 'ChatsController#index');//chats
Route::get('/messages', 'ChatsController#fetchMessages');//messages
Route::post('/messages', 'ChatsController#sendMessage');//messages
Route::get('/dashboard', 'Admin\DashboardController#dbcheck');//DATABASE
Route::get('/user-edit/{id}', 'HomeController#registeredit');
Route::get('/role-edit/{id}', 'Admin\DashboardController#registeredit');//edit user
Route::put('/role-register-update/{id}', 'Admin\DashboardController#registerupdate');
Auth::routes();
Route::get('/home', 'HomeController#index')->name('home');
Route::get('store_image', 'StoreImageController#index');
Route::post('store_image/insert_image', 'StoreImageController#insert_image');
Route::get('store_image/fetch_image/{id}', 'StoreImageController#fetch_image');
Route::get('/page',array('as'=>'jquery.treeview','uses'=>'Admin\DepartmentController#treeView'));
Route::get('/pageusers', 'Admin\DepartmentController#usersdep');
Department.php
<?php
namespace App;
use Illuminate\Database\Eloquent\Model;
class Department extends Model
{
protected $table = 'departments';
protected $fillable = [
'name',
];
protected $primaryKey = 'id';
public function users()
{
// return $this->belongsTo(User::class);
return $this->hasMany(User::class,'department','id');
}
//category has childs
public function childs() {
return $this->hasMany('App\Department','parent','id') ;
/*
childs() method with hasMany relationship.
hasMany relationship in Laravel tell us that they have multiple childs.
Here I am creating relationship based on parent and each category has their parent if parent id is 0 it means it is root category.*/
}
}
create_departments_table
<?php
use Illuminate\Database\Migrations\Migration;
use Illuminate\Database\Schema\Blueprint;
use Illuminate\Support\Facades\Schema;
class CreateDepartmentsTable extends Migration
{
/**
* Run the migrations.
*
* #return void
*/
public function up()
{
Schema::create('departments', function (Blueprint $table) {
$table->bigIncrements('id');
$table->string('name');
$table->integer('parent');
$table->timestamps();
});
}
/**
* Reverse the migrations.
*
* #return void
*/
public function down()
{
Schema::dropIfExists('departments');
}
}

Answer 1

Alternative answer
Model
A Department model might be associated with one parent. To define this relationship, place a parent method on the model. The parent method should call the hasOne method and return its result:
class Department extends Model
{
protected $fillable = [
'name',
'parent_id',
];
public function parent()
{
return $this->hasOne(Department::class, 'id', 'parent_id');
}
}
Migration
Schema::create('departments', function (Blueprint $table) {
$table->bigIncrements('id');
$table->string('name');
$table->unsignedBigInteger('parent_id')->nullable();
$table->timestamps();
$table->foreign('parent_id')->references('id')->on('departments');
});
Usage
Once the relationship has been defined, you can retrieve the parent :
$departments = Department::get();
foreach ($departments as $department) {
if ($parent = $item->parent) {
dd($department->name, $parent->name);
}
else{
dd('This department is a parent')
}
}

Answer 2

You need to pass the correct department id.
public function index()
{
$departments = DB::table('departments')->select('departments.*')->get();
return view('admin.department', compact('departments'));
}
And view:
#foreach($departments as $department)
<tr>
<td>{{ $department->id }}</td>
<td>{{ $department->name }}</td>
#foreach($departments as $parent)
#if( $department->parent === $parent->id )
<td>{{ $department->name }}</td>
#endif
#endforeach
<tr>
#endforeach

Answer 3

Just define a relation in Department model
public function parentDepartment()
{
return $this->belongsTo(self::class, 'parent');
}
and in index method load it
public function index()
{
$departments = Department::with('parentDepartment')->get();
}