I am developing a Laravel application. I am using MySQL for the database. I have created a model class and am trying to run the migration on it. But when, I run migration, I am getting error with adding the foreign key constraint. This is what I have done so far.
First I have migrated the built in Laravel user model running this command.
php artisan migrate
The users table was created in the database.
Then I created another model running this command.
php artisan make:model TodoItem -m
Then I added the following code to the migration file.
class CreateTodoItemsTable extends Migration
{
/**
* Run the migrations.
*
* @return void
*/
public function up()
{
Schema::create('todo_items', function (Blueprint $table) {
$table->text('about');
$table->integer('user_id');
$table->increments('id');
$table->timestamps();
$table->foreign('user_id')->references('id')->on('users')->onDelete('cascade');
});
}
/**
* Reverse the migrations.
*
* @return void
*/
public function down()
{
Schema::dropIfExists('todo_items');
}
}
AS you can see above, I am building the relationship between users table and todo_items table by adding a foreign key to the todo_items table. Then, I tried to migrate the TodoItem model by running this command.
php artisan migrate
When I run the command, I got this error.
Illuminate\Database\QueryException : SQLSTATE[HY000]: General error: 1215 Cannot add foreign key constraint (SQL: alter table `todo_items` add constraint `todo_items_user_id_foreign` foreign key (`user_id`) references `users` (`id`) on delete cascade)
at /var/www/vendor/laravel/framework/src/Illuminate/Database/Connection.php:664
660| // If an exception occurs when attempting to run a query, we'll format the error
661| // message to include the bindings with SQL, which will make this exception a
662| // lot more helpful to the developer instead of just the database's errors.
663| catch (Exception $e) {
> 664| throw new QueryException(
665| $query, $this->prepareBindings($bindings), $e
666| );
667| }
668|
Exception trace:
1 PDOException::("SQLSTATE[HY000]: General error: 1215 Cannot add foreign key constraint")
/var/www/vendor/laravel/framework/src/Illuminate/Database/Connection.php:458
2 PDOStatement::execute()
/var/www/vendor/laravel/framework/src/Illuminate/Database/Connection.php:458
Please use the argument -v to see more details.
I did the same in my previous project which is using Postgresql. I was working fine. For this project, I am using MySQL database and now it is giving me the above error.