Drop foreign and primary key in migration in laravel
Blueprint class offers dropForeign and dropPrimary methods that allow you to remove foreign key constraints and primary key.
The following should do the trick:
public function down()
{
Schema::table('role_user', function (Blueprint $table) {
$table->dropForeign('role_user_role_id_foreign');
$table->dropForeign('role_user_user_id_foreign');
$table->dropPrimary();
});
}