Laravel 回显视图中相关表中值的名称

请注意：我对laravel和编程基本上是新手

所以我在“用户”和“角色”之间有一个多对多的关系，使用这个新东西，我刚刚学习了一个透视表“角色\用户”。现在，我想显示我的用户列表以及他们拥有的角色的名称

用户迁移

use Illuminate\Database\Migrations\Migration;
use Illuminate\Database\Schema\Blueprint;
use Illuminate\Support\Facades\Schema;

class CreateUsersTable extends Migration
{

    public function up()
    {
        Schema::create('users', function (Blueprint $table) {
            $table->bigIncrements('id');
            $table->string('name');
            $table->string('email')->unique();
            $table->timestamp('email_verified_at')->nullable();
            $table->string('password');
            $table->rememberToken();
            $table->timestamps();
        });
    }

    public function down()
    {
        Schema::dropIfExists('users');
    }
}

use Illuminate\Database\Migrations\Migration;
use Illuminate\Database\Schema\Blueprint;
use Illuminate\Support\Facades\Schema;

class CreateRolesTable extends Migration
{
    public function up()
    {
        Schema::create('roles', function (Blueprint $table) {
            $table->bigIncrements('id');
            $table->string('name');
        });
    }

    public function down()
    {
        Schema::dropIfExists('roles');
    }
}

use Illuminate\Database\Migrations\Migration;
use Illuminate\Database\Schema\Blueprint;
use Illuminate\Support\Facades\Schema;

class CreateRoleUserTable extends Migration
{
    public function up()
    {
        Schema::create('role_user', function (Blueprint $table) {
            $table->bigInteger('role_id')->unsigned();
            $table->bigInteger('user_id')->unsigned();
        });
    }

    public function down()
    {
        Schema::dropIfExists('role_user');
    }
}

角色迁移

use Illuminate\Database\Migrations\Migration;
use Illuminate\Database\Schema\Blueprint;
use Illuminate\Support\Facades\Schema;

class CreateUsersTable extends Migration
{

    public function up()
    {
        Schema::create('users', function (Blueprint $table) {
            $table->bigIncrements('id');
            $table->string('name');
            $table->string('email')->unique();
            $table->timestamp('email_verified_at')->nullable();
            $table->string('password');
            $table->rememberToken();
            $table->timestamps();
        });
    }

    public function down()
    {
        Schema::dropIfExists('users');
    }
}

use Illuminate\Database\Migrations\Migration;
use Illuminate\Database\Schema\Blueprint;
use Illuminate\Support\Facades\Schema;

class CreateRolesTable extends Migration
{
    public function up()
    {
        Schema::create('roles', function (Blueprint $table) {
            $table->bigIncrements('id');
            $table->string('name');
        });
    }

    public function down()
    {
        Schema::dropIfExists('roles');
    }
}

use Illuminate\Database\Migrations\Migration;
use Illuminate\Database\Schema\Blueprint;
use Illuminate\Support\Facades\Schema;

class CreateRoleUserTable extends Migration
{
    public function up()
    {
        Schema::create('role_user', function (Blueprint $table) {
            $table->bigInteger('role_id')->unsigned();
            $table->bigInteger('user_id')->unsigned();
        });
    }

    public function down()
    {
        Schema::dropIfExists('role_user');
    }
}

角色\用户迁移

use Illuminate\Database\Migrations\Migration;
use Illuminate\Database\Schema\Blueprint;
use Illuminate\Support\Facades\Schema;

class CreateUsersTable extends Migration
{

    public function up()
    {
        Schema::create('users', function (Blueprint $table) {
            $table->bigIncrements('id');
            $table->string('name');
            $table->string('email')->unique();
            $table->timestamp('email_verified_at')->nullable();
            $table->string('password');
            $table->rememberToken();
            $table->timestamps();
        });
    }

    public function down()
    {
        Schema::dropIfExists('users');
    }
}

use Illuminate\Database\Migrations\Migration;
use Illuminate\Database\Schema\Blueprint;
use Illuminate\Support\Facades\Schema;

class CreateRolesTable extends Migration
{
    public function up()
    {
        Schema::create('roles', function (Blueprint $table) {
            $table->bigIncrements('id');
            $table->string('name');
        });
    }

    public function down()
    {
        Schema::dropIfExists('roles');
    }
}

use Illuminate\Database\Migrations\Migration;
use Illuminate\Database\Schema\Blueprint;
use Illuminate\Support\Facades\Schema;

class CreateRoleUserTable extends Migration
{
    public function up()
    {
        Schema::create('role_user', function (Blueprint $table) {
            $table->bigInteger('role_id')->unsigned();
            $table->bigInteger('user_id')->unsigned();
        });
    }

    public function down()
    {
        Schema::dropIfExists('role_user');
    }
}

用户模型

namespace App;

use Illuminate\Contracts\Auth\MustVerifyEmail;
use Illuminate\Foundation\Auth\User as Authenticatable;
use Illuminate\Notifications\Notifiable;

class User extends Authenticatable
{
    use Notifiable;

    protected $fillable = [
        'name', 'email', 'password', 'roles_id'
    ];

    protected $hidden = [
        'password', 'remember_token',
    ];

    protected $casts = [
        'email_verified_at' => 'datetime',
    ];

    public function roles()
    {
        return $this->belongsToMany('App\Role');
    }

    public function authorizeRoles($roles)
    {
        if (is_array($roles)) {
            return $this->hasAnyRole($roles) || 
                    abort(401, 'This action is unauthorized.');
        }
        return $this->hasRole($roles) || 
                abort(401, 'This action is unauthorized.');
    }
    /**
    * Check multiple roles
    * @param array $roles
    */
    public function hasAnyRole($roles)
    {
        return null !== $this->roles()->whereIn(‘name’, $roles)->first();
    }
    /**
    * Check one role
    * @param string $role
    */
    public function hasRole($role)
    {
        return null !== $this->roles()->where(‘name’, $role)->first();
    }
}

namespace App;

use Illuminate\Database\Eloquent\Model;

class Role extends Model
{

    public $timestamps = false;

    public function users()
    {
        return $this->belongsToMany('App\User');
    }
}

public function users()
{
    return $this->belongsToMany('App\User', 'role_users'); //plural name
}

榜样

namespace App;

use Illuminate\Contracts\Auth\MustVerifyEmail;
use Illuminate\Foundation\Auth\User as Authenticatable;
use Illuminate\Notifications\Notifiable;

class User extends Authenticatable
{
    use Notifiable;

    protected $fillable = [
        'name', 'email', 'password', 'roles_id'
    ];

    protected $hidden = [
        'password', 'remember_token',
    ];

    protected $casts = [
        'email_verified_at' => 'datetime',
    ];

    public function roles()
    {
        return $this->belongsToMany('App\Role');
    }

    public function authorizeRoles($roles)
    {
        if (is_array($roles)) {
            return $this->hasAnyRole($roles) || 
                    abort(401, 'This action is unauthorized.');
        }
        return $this->hasRole($roles) || 
                abort(401, 'This action is unauthorized.');
    }
    /**
    * Check multiple roles
    * @param array $roles
    */
    public function hasAnyRole($roles)
    {
        return null !== $this->roles()->whereIn(‘name’, $roles)->first();
    }
    /**
    * Check one role
    * @param string $role
    */
    public function hasRole($role)
    {
        return null !== $this->roles()->where(‘name’, $role)->first();
    }
}

namespace App;

use Illuminate\Database\Eloquent\Model;

class Role extends Model
{

    public $timestamps = false;

    public function users()
    {
        return $this->belongsToMany('App\User');
    }
}

public function users()
{
    return $this->belongsToMany('App\User', 'role_users'); //plural name
}

我的观点

@extends('layouts/app')

@section('content')

<div class="row">
        <div class="col-md-12">
            <div class="card">
                <div class="card-header">
                    <h4>Users</h4>
                </div>

                <div class="panel-body">
                    @if (count($users) > 0)
                    <table class="table">
                        <thead>
                            <tr>
                                <th>Name</th>
                                <th>Email</th>
                                <th>Created on</th>
                                <th>Role</th>
                            </tr>
                        </thead>
                    @foreach ($users as $user)
                        <tr>
                                <td><em>{{$user->name}}</em></td>
                                <td><em>{{$user->email }} </em></td>
                                <td><em>{{$user->created_at}}</em></td>
                                <td><em>{{$user->roles->name}} </em></td> 
                                <td>
                                    <span class="table-remove">
                                         {!!Form::open(['action' =>['userController@destroy', $user->id], 'method' => 'POST'])!!}
                                            {{Form::hidden('_method', 'DELETE')}}
                                            {{ Form::button('<i class="fas fa-trash-alt" aria-hidden="true"></i>', ['class' => 'btn btn-danger btn-sm', 'type' => 'submit']) }}
                                        {!!Form::close()!!}
                                    </span>
                                </td>                                
                        </tr>
                    @endforeach
                    </table>
                </div>
            </div>
        </div>
    </div>
@else
    <p>No users found</p>

@endif

现在我得到了一个错误：

此集合实例上不存在属性[name]。（视图：C:\xampp\htdocs\Laravel\AmbitieProject\resources\views\users\index.blade.php）

---

我尝试回显“$user->roles->name”，我认为这应该适用于一对多关系，但我不确定如何使用多对多关系回显角色的名称。您定义关系时出错了

请在关系中定义

pivot

表

榜样

namespace App;

use Illuminate\Contracts\Auth\MustVerifyEmail;
use Illuminate\Foundation\Auth\User as Authenticatable;
use Illuminate\Notifications\Notifiable;

class User extends Authenticatable
{
    use Notifiable;

    protected $fillable = [
        'name', 'email', 'password', 'roles_id'
    ];

    protected $hidden = [
        'password', 'remember_token',
    ];

    protected $casts = [
        'email_verified_at' => 'datetime',
    ];

    public function roles()
    {
        return $this->belongsToMany('App\Role');
    }

    public function authorizeRoles($roles)
    {
        if (is_array($roles)) {
            return $this->hasAnyRole($roles) || 
                    abort(401, 'This action is unauthorized.');
        }
        return $this->hasRole($roles) || 
                abort(401, 'This action is unauthorized.');
    }
    /**
    * Check multiple roles
    * @param array $roles
    */
    public function hasAnyRole($roles)
    {
        return null !== $this->roles()->whereIn(‘name’, $roles)->first();
    }
    /**
    * Check one role
    * @param string $role
    */
    public function hasRole($role)
    {
        return null !== $this->roles()->where(‘name’, $role)->first();
    }
}

namespace App;

use Illuminate\Database\Eloquent\Model;

class Role extends Model
{

    public $timestamps = false;

    public function users()
    {
        return $this->belongsToMany('App\User');
    }
}

public function users()
{
    return $this->belongsToMany('App\User', 'role_users'); //plural name
}

---

您的透视表将返回一个Laravel。因此，如果不先获取记录，则无法访问记录的属性

如果有许多角色是可能的，我假设这是真的，因为您选择了透视表路线，您应该这样做，以逗号分隔的列表形式列出它们：

@如果（$user->roles->count（）>0）
{{$user->roles->内爆（'name'，'，'）}
@恩迪夫

如果只有一个角色，则只需使用

first（）

获取第一条记录：

@如果（$user->roles->count（）>0）
{{$user->roles->first（）->name}
@恩迪夫

您可以共享控制器吗？

$user->roles

将返回与用户关联的一个或多个角色的集合。然后，您需要在循环中获取每个角色，或者如果只有一个角色，请使用

$user->roles->first（）->name

获取集合中的第一个条目：$user->roles->first（）->name有效，谢谢！我补充了一句作为回答。我不知道，谢谢。但这并没有解决我的问题。