persist() and flush() inside loop - Doctrine

Question

I want to know how many times the ff: codes will make a roundway trip to the database.

foreach ($recipients as $recipient) {
    $received_email = new ReceivedEmail();
    $received_email->setRecipient($recipient);
    $received_email->setEmail($email);

    $entityManager->persist($received_email);
    $entityManager->flush(); 
}

$recipients is an array of User objects with One-to-Many relationship with ReceivedEmail

$email is an object with One-to-Many relationship with ReceivedEmail.

If for instance $recipients has five entities, does the loop generates a total of five trips to database? Or only one?

Is the above example the most optimized way to insert new ReceivedEmail records?

Thanks

Answer 1

There will be generated one INSERT statement for each persist.

What is more, you can just display yours SQL statements for debug, just configure Doctrine for logging: https://stackoverflow.com/a/4585421/1815881

In your case:

$entityManager->getConfiguration()->
                setSQLLogger(new \Doctrine\DBAL\Logging\EchoSQLLogger());

For many inserts you should consider the batch prcessing:

• https://www.doctrine-project.org/projects/doctrine-orm/en/2.6/reference/batch-processing.html

Hope I have revealed the problem.