Illuminate\Database\QueryException : SQLSTATE[42000]: Syntax error or access violation: 1071 Speciif

问题：运行迁移文件报错 

   Illuminate\Database\QueryException

  SQLSTATE[42000]: Syntax error or access violation: 1071 Specified key was too long; max key length is 1000 bytes (SQL: alter table `users` add unique `users_email_unique`(`email`))

  at E:\phpstudy_pro\WWW\shopapi\vendor\laravel\framework\src\Illuminate\Database\Connection.php:712
    708▕         // If an exception occurs when attempting to run a query, we'll format the error
    709▕         // message to include the bindings with SQL, which will make this exception a
    710▕         // lot more helpful to the developer instead of just the database's errors.
    711▕         catch (Exception $e) {
  ➜ 712▕             throw new QueryException(
    713▕                 $query, $this->prepareBindings($bindings), $e
    714▕             );
    715▕         }
    716▕     }

  1   E:\phpstudy_pro\WWW\shopapi\vendor\laravel\framework\src\Illuminate\Database\Connection.php:501
      PDOException::("SQLSTATE[42000]: Syntax error or access violation: 1071 Specified key was too long; max key length is 1000 bytes")

  2   E:\phpstudy_pro\WWW\shopapi\vendor\laravel\framework\src\Illuminate\Database\Connection.php:501
      PDOStatement::execute()

这是由于Laravel 默认使用 utf8mb4 字符， 包括支持在数据库存储「 表情」 。 如果你正在运行的 MySQL release 版本低于5.7.7 或 MariaDB release
版本低于10.2.2 ， 为了MySQL为它们创建索引， 你可能需要手动配置迁移生成的默认字符串长度， 你可以通过调用 AppServiceProvider 中的
Schema::defaultStringLength 方法来配置它：

解决办法

1.  E:\phpstudy_pro\WWW\shopapi\app\Providers\AppServiceProvider.php

<?php

namespace App\Providers;

use Illuminate\Support\ServiceProvider;
use Illuminate\Support\Facades\Schema;

class AppServiceProvider extends ServiceProvider
{
    /**
     * Register any application services.
     *
     * @return void
     */
    public function register()
    {
        //
    }

    /**
     * Bootstrap any application services.
     *
     * @return void
     */
    public function boot()
    {
        //
        Schema::defaultStringLength(191);

    }
}

这两句代码 加上

use Illuminate\Support\Facades\Schema;


public function boot()
    {
        //
        Schema::defaultStringLength(191);
    }

再次执行迁移文件：

 php artisan migrate