1-进入/config/database.php，找到这些行

'mysql' => [
    ...,
    'charset' => 'utf8mb4',
    'collation' => 'utf8mb4_unicode_ci',
    ...,
    'engine' => null,
 ]

并更改为:

'mysql' => [
    ...,
    'charset' => 'utf8',
    'collation' => 'utf8_unicode_ci',
    ...,
    'engine' => 'InnoDB',
 ]

2-运行php artisan config:cache重新配置laravel

3-删除数据库中现有的表，然后再次运行php artisan migrate

模式:defaultStringLength (191);将默认定义所有字符串191的长度，这可能会破坏您的数据库。你不能走这条路。

只需在数据库迁移类中定义任何特定列的长度。例如，我在CreateUsersTable类中定义了“name”，“username”和“email”，如下所示:

public function up()
    {
        Schema::create('users', function (Blueprint $table) {
            $table->increments('id');
            $table->string('name', 191);
            $table->string('username', 30)->unique();
            $table->string('email', 191)->unique();
            $table->string('password');
            $table->rememberToken();
            $table->timestamps();
        });
    }

对于不想更改AppServiceProvider.php的人。 (在我看来，仅仅为了迁移而更改AppServiceProvider.php是一个坏主意)

您可以将数据长度添加回database/migrations/下的迁移文件，如下所示:

create_users_table.php

$table->string('name',64);
$table->string('email',128)->unique();

create_password_resets_table.php

$table->string('email',128)->index();

如果您想在AppServiceProvider中进行更改，那么您需要在迁移中定义电子邮件字段的长度。只需将第一行代码替换为第二行。

create_users_table

$table->string('email')->unique();
$table->string('email', 50)->unique();

create_password_resets_table

$table->string('email')->index();
$table->string('email', 50)->index();

在成功更改之后，您可以运行迁移。 注意:首先你必须从数据库中删除(如果你有)users表，password_resets表，并从迁移表中删除users和password_resets条目。

如前所述，我们在App/Providers中添加到AppServiceProvider.php

use Illuminate\Support\Facades\Schema;  // add this

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

你可以在下面的链接中看到更多细节(搜索“索引长度& MySQL / MariaDB”) https://laravel.com/docs/5.5/migrations

BUT WELL THAT's not what I published all about! the thing is even when doing the above you will likely to get another error (that's when you run php artisan migrate command and because of the problem of the length, the operation will likely stuck in the middle. solution is below, and the user table is likely created without the rest or not totally correctly) we need to roll back. the default roll back will not work. because the operation of migration didn't like finish. you need to delete the new created tables in the database manually.

我们可以这样做使用修补器如下所示:

L:\todos> php artisan tinker

Psy Shell v0.8.15 (PHP 7.1.10 — cli) by Justin Hileman

>>> Schema::drop('users')

=> null

我自己有一个问题与用户表。

之后你就可以开始了

PHP artisan migrate:回滚

PHP工匠迁移

我只是把这个答案加在这里，因为这对我来说是最快的解决方法。只需要将默认的数据库引擎设置为'InnoDB'

/ config / database.php

'mysql' => [
    ...,
    ...,
    'engine' => 'InnoDB',
 ]

然后运行PHP artisan config:cache来清除和刷新配置缓存

编辑: 这里找到的答案可能解释了这一事件背后的原因