Migrate data between tables efficiently

Question

I wrote a very simple quick and easy script to migrate a bunch of data to another table in my database.

Can I accomplish this task without using so many foreach loops?
I realize I'm imputting similar data in each of my loops and it just seems redundant and wrong.

I thought of using array_merge on talkers, pros & anons and I thought that because each of the second loops use the same field, I would write code to retrieve getYI and then write code to determine if it belonged to a talker, anon, or pro.
However I wasn't sure if either of those solutions would make my script any more efficient/better.

Certainly any insight would be appreciated. Thanks in advance!

And if it helps I'm using Symfony 2.3.

public function migratingDataScript()
{
    $em = $this->getDoctrine()->getManager();

    $talkers = $em->getRepository('AppBundle:Talker')->findAll();
    $anons = $em->getRepository('AppBundle:Anon')->findAll();
    $pros = $em->getRepository('AppBundle:Pro')->findAll();

    foreach ($talkers as $talker) {
        echo "Talker: ".$talker->getId()."<br>";
        foreach ($talker->getYI() as $year => $status) {
            $rounds = $em->getRepository('AppBundle:Round')->findByYear($year);
            foreach ($rounds as $round) {
                $newTalkerInvitation = new Invitation($round);
                $newTalkerInvitation->setStatus($status);
                $newTalkerInvitation->setTalker($talker);
                // $newTalkerInvitation->setNumAt(); No Data For Talker
                // $newTalkerInvitation->setStart(); No Data For Talker
                $em->persist($newTalkerInvitation);
            }
        }
    }//Ends Talker Migration

    foreach ($anons as $anon) {
        echo "Anon: ".$anon->getId()."<br>";
        foreach ($anon->getYI() as $year => $status) {
            $rounds = $em->getRepository('AppBundle:Round')->findByYear($year);
            foreach ($rounds as $round) {
                $newAnonInvitation = new Invitation($round);
                $newAnonInvitation->setStatus($status);
                $newAnonInvitation->setAnon($anon);
                // $newAnonInvitation->setNumAt(); No Data For Anon
                // $newAnonInvitation->setStart(); No Data For Anon
                $em->persist($newAnonInvitation);
            }
        }
    }//Ends Anon Migration

    foreach ($pros as $pro) {
        echo "Pro: ".$pro->getId()."<br>";
        foreach ($pro->getYI() as $year => $status) {
            $rounds = $em->getRepository('AppBundle:Round')->findByYear($year);
            foreach ($rounds as $round) {
                $newProInvitation = new Invitation($round);
                $newProInvitation->setStatus($status);
                $newProInvitation->setPro($pro);
                if(is_null($pro->getNumOfAttempts())){
                    $newProInvitation->setNumAt('0');
                }else {
                    $newProInvitation->setNumAt($pro->getNumOfAttempts());
                }
                // $newProInvitation->setStart(); No Data For Pro
                $em->persist($newProInvitation);
            }
        }
    }//Ends Pro Migration

    $em->flush();
    echo "Completed.";
    die;
}

Answer 1

Can I accomplish this task without using so many foreach loops?

Depends.

If you want to stick with database-agnostic abstraction such as Doctrine, there is no way to avoid loops.

But if you want an efficient solution, you can write a database-specific query to copy all records in a single query. For example, for mysql it would be something like

INSERT INTO invitation (field1, field2, status, talker) 
  SELECT field1, field2, ?, ? FROM talker

and then bind $status and $talker to this query.