마이그레이션에러 SQLSTATE[HY000]: General error: 3780

   Illuminate\Database\QueryException  : SQLSTATE[HY000]: General error: 3780 Referencing column 'user_id' and referenced column 'id' in foreign key constraint 'questions_user_id_foreign' are incompatible. (SQL: alter table `questions` add constraint `questions_user_id_foreign` foreign key (`user_id`) references `users` (`id`) on delete cascade on update cascade)

  at /Users/wonhochoi/laravel-qa/vendor/laravel/framework/src/Illuminate/Database/Connection.php:669

    665|         // If an exception occurs when attempting to run a query, we'll format the error

    666|         // message to include the bindings with SQL, which will make this exception a

    667|         // lot more helpful to the developer instead of just the database's errors.

    668|         catch (Exception $e) {

  > 669|             throw new QueryException(

    670|                 $query, $this->prepareBindings($bindings), $e

    671|             );

    672|         }

    673| 

  Exception trace:

  1   PDOException::("SQLSTATE[HY000]: General error: 3780 Referencing column 'user_id' and referenced column 'id' in foreign key constraint 'questions_user_id_foreign' are incompatible.")

      /Users/wonhochoi/laravel-qa/vendor/laravel/framework/src/Illuminate/Database/Connection.php:463

  2   PDOStatement::execute()

      /Users/wonhochoi/laravel-qa/vendor/laravel/framework/src/Illuminate/Database/Connection.php:463

  Please use the argument -v to see more details.

$table->unsignedInteger('user_id');

수정

$table->unsignedBigInteger('user_id');

다시 마이그레이션 실행한다.

https://qiita.com/yoshinyan/items/1f96eec326b9e5b863c4