Laravel 5.5 不能掉外来

Question

我的trophies表：

public function up()
{
    Schema::create('trophies', function (Blueprint $table) {
        $table->increments('id');

        $table->integer('tournament_id')->unsigned()->nullable();
        $table->foreign('tournament_id')
            ->references('id')
            ->on('tournaments')
            ->onUpdate('cascade')
            ->onDelete('cascade')
        ;

        $table->integer('season_id')->unsigned()->nullable();
        $table->foreign('season_id')
            ->references('id')
            ->on('seasons')
            ->onUpdate('cascade')
            ->onDelete('cascade')
        ;

        $table->integer('user_id')->nullable()->unsigned();
        $table->foreign('user_id')
            ->references('id')
            ->on('users')
            ->onUpdate('cascade')
            ->onDelete('cascade');
        ;

        $table->integer('team_id')->nullable()->unsigned();
        $table->foreign('team_id')
            ->references('id')
            ->on('teams')
            ->onUpdate('cascade')
            ->onDelete('cascade')
        ;
        $table->timestamps();
    });
}

现在我想删除外键 season_id

public function up()
{
    Schema::table('trophies', function (Blueprint $table) {
        $table->dropForeign(['season_id']);
    });
}

当我运行 php artisan migrate 时，我收到下一个错误：

In Connection.php line 664:

  SQLSTATE[42000]: Syntax error or access violation: 1091 Can't DROP 'trophies_season_id_foreign'; check that column/key exists (SQL: alter table `trophies` drop foreign key `trophies_season_id_foreign`)

也许当我将我的项目从 laravel 5.0 升级到 laravel 5.5 时出现了一些问题？

在 phpMyAdmin 中：

    CREATE TABLE `trophies` (
 `id` int(10) unsigned NOT NULL AUTO_INCREMENT,
 `tournament_id` int(10) unsigned DEFAULT NULL,
 `season_id` int(10) unsigned DEFAULT NULL,
 `user_id` int(10) unsigned DEFAULT NULL,
 `team_id` int(10) unsigned DEFAULT NULL,
 `created_at` timestamp NOT NULL DEFAULT '0000-00-00 00:00:00',
 `updated_at` timestamp NOT NULL DEFAULT '0000-00-00 00:00:00',
 `tourney_id` int(10) unsigned NOT NULL,
 `tourney_type` varchar(255) COLLATE utf8_unicode_ci NOT NULL,
 PRIMARY KEY (`id`),
 KEY `trophies_tournament_id_foreign` (`tournament_id`) USING BTREE,
 KEY `trophies_season_id_foreign` (`season_id`) USING BTREE,
 KEY `trophies_user_id_foreign` (`user_id`) USING BTREE,
 KEY `trophies_team_id_foreign` (`team_id`) USING BTREE,
 KEY `trophies_tourney_id_tourney_type_index` (`tourney_id`,`tourney_type`),
 CONSTRAINT `trophies_ibfk_1` FOREIGN KEY (`season_id`) REFERENCES `seasons` (`id`) ON DELETE CASCADE ON UPDATE CASCADE,
 CONSTRAINT `trophies_ibfk_2` FOREIGN KEY (`team_id`) REFERENCES `teams` (`id`) ON DELETE CASCADE ON UPDATE CASCADE,
 CONSTRAINT `trophies_ibfk_3` FOREIGN KEY (`tournament_id`) REFERENCES `tournaments` (`id`) ON DELETE CASCADE ON UPDATE CASCADE,
 CONSTRAINT `trophies_ibfk_4` FOREIGN KEY (`user_id`) REFERENCES `users` (`id`) ON DELETE CASCADE ON UPDATE CASCADE
) ENGINE=InnoDB AUTO_INCREMENT=130 DEFAULT CHARSET=utf8 COLLATE=utf8_unicode_ci

Answer 1

试试这个...你需要删除关系和列。

$table->dropForeign(['season_id']);
$table->dropColumn('season_id');