is it okay to write transactions like this, and do you need custom exceptions?

DB::beginTransaction();
try{
    // 
    $adminRoleObj = new AdminRole;
    $result = $adminRoleObj->deleteAdminRole($admin->id);

    // 
    $result = $admin->delete();

    DB::commit();
}catch(\Exception $e){
    $result = false;
    Log::error("admin:delete ".$e->getMessage());
    DB::rollBack();
}