Question

我使用无符号user_id创建了迁移。如何在新迁移中修改user_id以使其成为nullable()？

Schema::create('throttle', function(Blueprint $table)
{
    $table->increments('id');
    // this needs to also be nullable, how should the next migration be?
    $table->integer('user_id')->unsigned();
}

Answer 1

Laravel 5现在支持更改列..

官方文档

的示例

Schema::table('users', function($table)
{
    $table->string('name', 50)->nullable()->change();
});

来源：http://laravel.com/docs/5.0/schema#changing-columns

Laravel 4不支持修改列。你必须编写raw sql命令。

  // getting Laravel App Instance
   $app = app();

  // getting laravel main version
   $laravelVer = explode('.',$app::VERSION);

    switch ($laravelVer[0]) {

        case('5') :                
            Schema::table('pro_categories_langs', function(Blueprint $t) {
                $t->string('name', 100)->nullable()->default(null)->change();
            });               
            break;                
        /**
         * it is not L5 !!
         */
        default :                
             DB::statement('ALTER TABLE `pro_categories_langs` MODIFY `name` VARCHAR(100) NULL;');                                  
    }

Answer 2

我假设您正在尝试编辑已添加数据的列，因此在不丢失数据的情况下，删除列并再次添加为可为空的列是不可能的。我们将alter现有列。

但是，Laravel的架构构建器不支持修改除重命名列之外的列。因此，您需要运行原始查询来执行这些操作，如下所示：

function up()
{
    DB::statement('ALTER TABLE `throttle` MODIFY `user_id` INTEGER UNSIGNED NULL;');
}

为了确保您仍然可以回滚迁移，我们也会执行down()。

function down()
{
    DB::statement('ALTER TABLE `throttle` MODIFY `user_id` INTEGER UNSIGNED NOT NULL;');
}

需要注意的是，由于您要在可空和可空之间进行转换，因此您需要确保在迁移之前/之后清理数据。因此，请在迁移脚本中以两种方式执行此操作：

function up()
{
    DB::statement('ALTER TABLE `throttle` MODIFY `user_id` INTEGER UNSIGNED NULL;');
    DB::statement('UPDATE `throttle` SET `user_id` = NULL WHERE `user_id` = 0;');
}

function down()
{
    DB::statement('UPDATE `throttle` SET `user_id` = 0 WHERE `user_id` IS NULL;');
    DB::statement('ALTER TABLE `throttle` MODIFY `user_id` INTEGER UNSIGNED NOT NULL;');
}

Answer 3

Here's the complete answer for the future reader. Note that this is only possible in Laravel 5+.

First of all you'll need the doctrine/dbal package:

composer require doctrine/dbal

Now in your migration you can do this to make the column nullable:

public function up()
{
    Schema::table('users', function (Blueprint $table) {
        // change() tells the Schema builder that we are altering a table
        $table->integer('user_id')->unsigned()->nullable()->change();
    });
}

You may be wondering how to revert this operation. Sadly this syntax is not supported:

// Sadly does not work :'(
$table->integer('user_id')->unsigned()->change();

This is the correct syntax to revert the migration:

$table->integer('user_id')->unsigned()->nullable(false)->change();

Or, if you prefer, you can write a raw query:

public function down()
{
    /* Make user_id un-nullable */
    DB::statement('UPDATE `users` SET `user_id` = 0 WHERE `user_id` IS NULL;');
    DB::statement('ALTER TABLE `users` MODIFY `user_id` INTEGER UNSIGNED NOT NULL;');
}

Hopefully you'll find this answer useful. :)

Answer 4

他是 Laravel 5 的完整迁移：

nullable

关键是，您可以通过传递false作为参数来删除while (isspace(*end)) { end++; }。

Answer 5

如果您碰巧更改了列并偶然发现了

'Doctrine\DBAL\Driver\PDOMySql\Driver' not found

然后只需安装

composer require doctrine/dbal

Answer 6

添加到Dmitri Chebotarev答案，

如果您想一次更改多个列，可以执行以下操作

DB::statement('
     ALTER TABLE `events` 
            MODIFY `event_date` DATE NOT NULL,
            MODIFY `event_start_time` TIME NOT NULL,
            MODIFY `event_end_time` TIME NOT NULL;
');

Answer 7

加入Dmitri Chebotarev的答案，就像Laravel 5 +一样。

在要求 doctrine / dbal 包之后：

composer require doctrine/dbal

然后，您可以使用可为空的列进行迁移，如下所示：

public function up()
{
    Schema::table('users', function (Blueprint $table) {
        // change() tells the Schema builder that we are altering a table
        $table->integer('user_id')->unsigned()->nullable()->change();
    });
}

要恢复操作，请执行以下操作：

public function down()
{
    /* turn off foreign key checks for a moment */
    DB::statement('SET FOREIGN_KEY_CHECKS = 0');
    /* set null values to 0 first */
    DB::statement('UPDATE `users` SET `user_id` = 0 WHERE `user_id` IS NULL;');
    /* alter table */
    DB::statement('ALTER TABLE `users` MODIFY `user_id` INTEGER UNSIGNED NOT NULL;');
    /* finally turn foreign key checks back on */
    DB::statement('SET FOREIGN_KEY_CHECKS = 1');

}

Answer 8

对于Laravel 4.2，Unnawut的答案是最好的。但是如果你使用表前缀，那么你需要改变你的代码。

function up()
{
    $table_prefix = DB::getTablePrefix();
    DB::statement('ALTER TABLE `' . $table_prefix . 'throttle` MODIFY `user_id` INTEGER UNSIGNED NULL;');
}

为了确保您仍然可以回滚迁移，我们也会执行down()。

function down()
{
    $table_prefix = DB::getTablePrefix();
    DB::statement('ALTER TABLE `' . $table_prefix . 'throttle` MODIFY `user_id` INTEGER UNSIGNED NOT NULL;');
}

Answer 9

试一试：

$table->integer('user_id')->unsigned()->nullable();

Laravel迁移变为使列可以为空

9 个答案: