我正在学习Laravel，当我尝试通过artisantinker使用以下代码插入用户时$user=App\User::create(['username'=>'johnd','first_name'=>'john','last_name'=>'doe','email'=>'john@doe.com','password'=>'thisShouldBeRandom','shool_id'=>1,'type'=>'TEACHER']);它抛出这个错误:Illuminate\Database\QueryExceptionwithmessage'SQLSTATE[23000]:Integrit