如何在 laravel 用户删除中重置自动增量

就像其他人回答的那样，当您删除一行时，实际上没有必要将计数器往回移动.不过，您可以truncate张桌子，其中will delete all the table rows张并重置计数器.

对于应用了Foreign Key Constraints的表，不能使用truncate(truncate与delete不同，delete只是删除所有行，而keeping是自动递增计数器).

Hence, while using foreign key constrains, MySQL might stop you from truncating a table which has foreign key constraints applied to it.

您可以执行以下步骤来实现所需，但请注意，数据完整性可能存在风险.我只在testing purposes岁时用它.

1. 编辑DatabaseSeeder类(app/database/seeds/DatabaseSeeder.php提供)如下:

   <?php
   class DatabaseSeeder extends Seeder {
       /**
       * Run the database seeds.
       *
       * @return void
       */
       public function run()
       {
           Eloquent::unguard();
   
           // Disable Foreign key check for this connection before running seeders
           DB::statement('SET FOREIGN_KEY_CHECKS=0;');
   
           $this->call('UserTableSeeder');
           // ...
   
           // FOREIGN_KEY_CHECKS is supposed to only apply to a single
           // connection and reset itself but I like to explicitly
           // undo what I've done for clarity
           DB::statement('SET FOREIGN_KEY_CHECKS=1;');
       }
   }
   

2. 现在，Table Seeder类(本例中为UserTableSeeder，应在app/database/seeds/UserTableSeeder.php处创建)可以按如下方式调用截断表:

   <?php
   class UserTableSeeder extends Seeder {
   
       public function run()
       {
           // Truncate the table.
           DB::table('users')->truncate();
   
   
           // The auto-increment has been reset.
           // Now we can start adding users.
           User::create(
               array(
                   'email' => 'example@domain.com',
                   'password' => Hash::make('test')
               )
           );
       }
   }