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Difference between EntityManager::persist() and EntityManager::flush() methods in LaravelDoctrine

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 The EntityManager::persist() and EntityManager::flush() methods are both part of the LaravelDoctrine library and are used for managing entities in a database. However, they serve different purposes.

EntityManager::persist() is used to add a new entity instance to the EntityManager's list of managed entities, which will subsequently be saved to the database when the EntityManager's flush() method is called. Essentially, persist() schedules the entity for insertion into the database, but does not actually execute the SQL INSERT statement yet.

Here's an example:


<?php
$user = new User();
$user->setName('John Doe');

$entityManager->persist($user);
?>

In this example, we create a new User entity and set its name to "John Doe". We then pass this entity to the persist() method of the EntityManager object, which adds it to the list of managed entities.

EntityManager::flush(), on the other hand, is used to synchronize all changes made to managed entities with the database. This means that any changes that were made to managed entities using methods like persist() and remove() will be saved to the database when flush() is called. flush() executes all scheduled SQL statements in a single transaction.

Here's an example:


<?php
$user = $entityManager->find(User::class, 1);
$user->setName('Jane Doe');

$entityManager->flush();
?>

In this example, we retrieve an existing User entity with an ID of 1 from the database using the find() method of the EntityManager. We then change the user's name to "Jane Doe". Finally, we call the flush() method of the EntityManager, which will save the changes made to the User entity to the database.

In summary, persist() is used to schedule an entity for insertion into the database, while flush() is used to synchronize changes made to managed entities with the database.

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