Foreign Keys
There are two ways to reference foreign keys. This example uses a Parent-Child relationship and shows what to put in the child migration.
Long way with the option to use different keys:
$table->integer('child_id')->unsigned()->index();
$table->foreign('parent_id')->references('id')->on('parents')->onDelete('cascade');
Short hand single line:
table->foreignId('parent_id')->constrained()->cascadeOnDelete();
See further information here:
https://laravel.com/docs/10.x/migrations#foreign-key-constraintsForeign Key Constraints