Laravel 7.4 无法添加外键约束

Question

所以我在我的旧文件的template 之后创建了一个迁移文件，如下所示：

create_banners_table（这个WORKED）

class CreateBannersTable extends Migration
{
    /**
     * Run the migrations.
     *
     * @return void
     */
    public function up()
    {
        Schema::create('banners', function (Blueprint $table) {
            $table->bigIncrements('id');
            $table->integer('order');
            $table->string('published');
            $table->timestamps();
        });

        Schema::create('banner_translations', function (Blueprint $table) {
            $table->increments('id')->unsigned();
            $table->string('locale', 10)->index();
            $table->string('title');
            $table->string('url');
            $table->foreignId('banner_id')
                ->constrained()
                ->onDelete('cascade');
        });
    }

    /**
     * Reverse the migrations.
     *
     * @return void
     */
    public function down()
    {
        Schema::dropIfExists('banner_translations');
        Schema::dropIfExists('banners');
    }
}

这是create_managements_table（这个FAILED）：

class CreateManagementsTable extends Migration
{
    /**
     * Run the migrations.
     *
     * @return void
     */
    public function up()
    {
        Schema::create('managements', function (Blueprint $table) {
            $table->bigIncrements('id');
            $table->integer('order');
            $table->string('published');
            $table->string('name');
            $table->string('category')
                ->comment('board of commissioners', 'board of executives');
            $table->timestamps();
        });

        Schema::create('management_translations', function (Blueprint $table) {
            $table->increments('id')->unsigned();
            $table->string('locale', 10)->index();
            $table->string('description');
            $table->string('title');
            $table->foreignId('management_id')
                ->constrained()
                ->onDelete('cascade');
        });
    }

    /**
     * Reverse the migrations.
     *
     * @return void
     */
    public function down()
    {
        Schema::dropIfExists('management_translations');
        Schema::dropIfExists('managements');
    }
}

问题是，当我尝试基于此创建另一个迁移文件时，我收到了这个错误：

SQLSTATE[HY000]: General error: 1215 Cannot add foreign key constraint (SQL: alter table `management_translations` add constraint `management_translations_management_id_foreign` foreign key (`management_id`) references `management` (`id`) on delete cascade)

如您所见，两个转换表都引用了各自基表中的大整数（因此没有类型不匹配）。

为了进一步调查，我跑了SHOW ENGINE INNODB STATUS; 并检查了Latest Foreign Key Error 并得到以下信息：

------------------------
LATEST FOREIGN KEY ERROR
------------------------
2021-08-28 12:01:41 0x7f6f44091700 Error in foreign key constraint of table cemindo/#sql-200_7:
 foreign key (`management_id`) references `management` (`id`) on delete cascade:
Cannot resolve table name close to:
 (`id`) on delete cascade

Answer 1

management 可数这个词是否模棱两可，所以显然 Laravel 在这种情况下将其视为不可数。也就是说，Laravel 认为 management_id 对应的表名应该是 management 而不是 managements，这是一个不常见的复数形式。因此，您应该将基表重命名为 management 或使用以下外键 sytnax：

Schema::create('management_translations', function (Blueprint $table) {    
    $table->increments('id')->unsigned();
    $table->string('locale', 10)->index();
    $table->string('description');
    $table->string('title');
    $table->foreignId('management_id')
        ->constrained('managements')
        ->onDelete('cascade');
});

Answer 2

Schema::create('banner_translations', function (Blueprint $table) {
            $table->increments('banner_id')->unsigned();     //change this line
            $table->string('locale', 10)->index();
            $table->string('title');
            $table->string('url');
            $table->foreignId('banner_id')
                ->constrained()
                ->onDelete('cascade');
        });

我认为你应该先提供banner_id，然后提供foreignId。（相同的列名）

Answer 3

你可以像下面这样添加外键引用，

首先创建所有键，然后最后声明外键引用...您可以在Laravel Doc's 看到此方法...请参阅该链接的第一个示例

Schema::create('managements', function (Blueprint $table) {
        $table->bigIncrements('id');
        $table->integer('order');
        $table->string('published');
        $table->string('name');
        $table->string('category')
            ->comment('board of commissioners','board of executives');
        $table->timestamps();
});

Schema::create('management_translations', function (Blueprint $table) {
        $table->increments('id')->unsigned();
        $table->string('locale', 10)->index();
        $table->string('description');
        $table->string('title');
        $table->unsignedBigInteger('management_id');
        $table->foreign('management_id')
                ->references('id')
                ->on('managements');
                ->onDelete('cascade');
});

如果您在使用我的解决方案时遇到任何错误，请告诉我，我会更新我的答案

谢谢