laravel migration best way to add foreign key

Question

Simple question: I'm new to Laravel. I have this migration file:

Schema::create('lists', function(Blueprint $table) {
    $table->increments('id'); 
    $table->string('title', 255);
    $table->integer('user_id')->unsigned(); 
    $table->foreign('user_id')->references('id')->on('users'); 
    $table->timestamps();
});

I want to update it to add onDelete('cascade').

What's the best way to do this?

Answer 1

Inside the up() function

First, make your user_id field an index:

$table->index('user_id');

After that you 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 first, then do everything from scratch.

Inside the down() function

$table->dropForeign('lists_user_id_foreign');
$table->dropIndex('lists_user_id_index');
$table->dropColumn('user_id');