Laravel 6 数据库种子问题：表不存在

Question

我正在设计一个允许用户发布、评论和编辑书籍的网站。我目前正在处理每个用户的角色，并且遇到了向 user_role 播种的问题。我遇到了以下错误，但不知道为什么。

唯一的假设是它在某个地方被命名为 role_user，但看不到在哪里或为什么？

   Illuminate\Database\QueryException  : SQLSTATE[42S02]: Base table or view not found: 1146 Table 'dockerphp.role_user' doesn't exist (SQL: insert into `role_user` (`role_id`, `user_id`) values (1, 1))

  at /srv/app/vendor/laravel/framework/src/Illuminate/Database/Connection.php:669
    665|         // If an exception occurs when attempting to run a query, we'll format the error
    666|         // message to include the bindings with SQL, which will make this exception a
    667|         // lot more helpful to the developer instead of just the database's errors.
    668|         catch (Exception $e) {
  > 669|             throw new QueryException(
    670|                 $query, $this->prepareBindings($bindings), $e
    671|             );
    672|         }
    673|

  Exception trace:

  1   PDOException::("SQLSTATE[42S02]: Base table or view not found: 1146 Table 'dockerphp.role_user' doesn't exist")
      /srv/app/vendor/laravel/framework/src/Illuminate/Database/Connection.php:457

  2   PDO::prepare("insert into `role_user` (`role_id`, `user_id`) values (?, ?)")
      /srv/app/vendor/laravel/framework/src/Illuminate/Database/Connection.php:457

我的播种机是这样的：

<?php

use Illuminate\Database\Seeder;
use Illuminate\Support\Facades\Hash;
use App\User;
use App\Role;
class UsersTableSeeder extends Seeder
{
    /**
     * Run the database seeds.
     *
     * @return void
     */
    public function run()
    {
        User::truncate();
        DB::table('user_role')->truncate();

        $authorRole = Role::where('name', 'Author')->first();
        $editorRole = Role::where('name', 'Editor')->first();
        $readerRole = Role::where('name', 'Reader')->first();

        $Author = User::create([
            'name' => 'Test Author',
            'email' => 'Test@author.com',
            'password' => Hash::make('testtest')
        ]);

        $Editor = User::create([
            'name' => 'Test Editor',
            'email' => 'Test@editor.com',
            'password' => Hash::make('testtest')
        ]);

        $Reader = User::create([
            'name' => 'Test Reader',
            'email' => 'Test@reader.com',
            'password' => Hash::make('testtest')
        ]);

        $Author->roles()->attach($authorRole);
        $Editor->roles()->attach($editorRole);
        $Reader->roles()->attach($readerRole);
    }
}

上面的那个似乎是遇到问题的那个，因为下面的播种机工作得很好。

class RolesTableSeeder extends Seeder
{
    /**
     * Run the database seeds.
     *
     * @return void
     */
    public function run()
    {
        Role::truncate();
        Role::create(['name' => 'Author']);
        Role::create(['name' => 'Editor']);
        Role::create(['name' => 'Reader']);
    }
}

最后，我的数据库播种器如下所示：

class DatabaseSeeder extends Seeder
{
    /**
     * Seed the application's database.
     *
     * @return void
     */
    public function run()
    {
        $this->call(RolesTableSeeder::class);
        $this->call(UsersTableSeeder::class);
    }
}

• 角色模型如下：

<?php

namespace App;

use Illuminate\Database\Eloquent\Model;

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

和用户模型

<?php

namespace App;

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

class User extends Authenticatable
{
    use Notifiable;

    /**
     * The attributes that are mass assignable.
     *
     * @var array
     */
    protected $fillable = [
        'name', 'email', 'password', 'about', 'avatar' 
    ];

    /**
     * The attributes that should be hidden for arrays.
     *
     * @var array
     */
    protected $hidden = [
        'password', 'remember_token',
    ];

    /**
     * The attributes that should be cast to native types.
     *
     * @var array
     */
    protected $casts = [
        'email_verified_at' => 'datetime',
    ];

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

Answer 1

问题在于 Laravel 按字母顺序命名关系，因此它被存储为 user_role，而是存储为 role_user。 通过更改两种模型来解决： 来自

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

到

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