laravel migration best way to add foreign key
Firstly you have to make your user_id
field an index:
$table->index('user_id');
After that you can create a foreign key with an action on cascade:
$table->foreign('user_id')->references('id')->on('users')->onDelete('cascade');
If you want to do that with a new migration, you have to remove the index and foreign key firstly and do everything from scratch.
On down() function you have to do this and then on up() do what I've wrote above:
$table->dropForeign('lists_user_id_foreign');
$table->dropIndex('lists_user_id_index');
$table->dropColumn('user_id');
In Laravel 7 it can be done in one line
$table->foreignId('user_id')->constrained()->cascadeOnDelete();