我正在给Tickets Table添加一个外键。另一个表ticket_statuses。

在artisan中，我执行了以下命令： php artisan make：迁移add_ticket_status_to_tickets_table

这是迁移文件中的代码：

      class AddTicketStatusToTicketsTable extends Migration
    {
        /**
         * Run the migrations.
         *
         * @return void
         */
        public function up()
        {

            Schema::table('tickets', function ($table) {
                $table->integer('ticket_status_id')->unsigned();
                $table->foreign('ticket_status_id')->references('id')->on('ticket_statuses')->onDelete('cascade');
            });

        }
     }

之后，我尝试实现一种关系。这是我在Tickets Model中的代码：

class Ticket extends Model
{

    // Ticket __belongs_to__ Ticket Status
    public function ticket_status()
    {
        return $this->belongsTo('App\TicketStatus');
    }
}

在artisan中，我执行了php artisan迁移，但我遇到了一个错误

[Illuminate\Database\QueryException]
  SQLSTATE[23000]: Integrity constraint violation: 1452 Cannot add or update a child row: a foreign key constraint fails (`idealcrmalphadb`.`#sql-4ea_1ce`, CONSTRAINT `tickets_ticket_status_id_foreign` FOREIGN KEY (`ticket_status_id`) REFERENCES `tickets` (`id`) ON DELETE CASCADE) (SQL: alter table `tickets` add constraint tickets_ticket_status_id_foreign foreignkey (`ticket_status_id`) references `tickets` (`id`) on delete cascade)

 [PDOException]
  SQLSTATE[23000]: Integrity constraint violation: 1452 Cannot add or update a child row: a foreign key constraint fails (`idealcrmalphadb`.`#sql-4ea_1ce`, CONSTRAINT `tickets_ticket_status_id_foreign` FOREIGN KEY (`ticket_status_id`) REFERENCES `tickets` (`id`) ON DELETE CASCADE)

我是不是在模型部分搞错了？请帮帮忙