Doctrine2: Syncing Collections / Adding multiple Elements of which some might already exist - php

Question

So i have a string, representing several objects (tags in this case)
i.e.: "php,mysql,doctrine2"
Let's say my database already has "php" and "doctrine2".
Now i want the best way to add the missing elemets (in this case mysql).
Should i create an object for every element and just use persist/sync or something, or is there a better way?
I need all the objects at the end anyway to add them to a new object (with a simple many-to-many relation) anyway.
I'd be happy about any suggestions.

Answer 1

1) Pull out all your tag names with a single query into an array
2) Use array_filter along with a closure to detect tags not present in the dataset
3) Create an insert for the new tags
$currentTags = getCurrentTagsArray();
$newTags = explode(',', 'php,mysql,doctrine2');
$newTagsToSave = array_filter($currentTags, function($item) use ($newTags){
if (in_array($item, $newTags))
{
return false;
}
return true;
});
Or...
You can use Doctrine 2's ArrayCollection wrapper (\Doctrine\Common\Collections\ArrayCollection()) it has pretty much the same implementation above as a filter method (you still need to pass the closure).
$myCollection->filter($closure);

Answer 2

I had a similar problem where I had to synchronize an entity collection with an external source. However, my problem required not only additions, but also updates and deletes. I used code to diff the ArrayCollection with another array, and call CRUD methods add based on the differences. As far as I can tell from the docs, doctrine doesn't natively handle this. Average performance should be O(n) but takes some memory.
/**
* #param array $source - the array we are starting with
* #param array $new - the array we want to end with
* #param $fnHash - function used to determine object equality, not based on object id
* #param $fnUpdate - function to perform update of existing object, takes current object and new object as params
* #param $fnAdd - function to perform insert
* #param $fnDelete - function to perform delete
*/
public static function syncArrays(array $source, array $new,
$fnHash, $fnUpdate, $fnAdd, $fnDelete)
{
// make modifiable array copies mapped by hashes of the elements
$sourceKeys = array_map($fnHash, $source);
$hasKeys =count($sourceKeys) > 0;
$newarray = ($hasKeys) ? array_combine(array_map($fnHash, $new), $new) : $new;
if ($hasKeys) { // true => may have updates or deletes
$sourcearray = array_combine($sourceKeys, $source);
// updates
foreach ($sourceKeys as $hashkey) {
if (isset($sourcearray[$hashkey]) && isset($newarray[$hashkey])) {
$fnUpdate($sourcearray[$hashkey], $newarray[$hashkey]);
unset($sourcearray[$hashkey]);
unset($newarray[$hashkey]);
}
}
// deletes
foreach ($sourcearray as $entity) {
$fnDelete($entity);
}
}
//adds
foreach ($newarray as $entity) {
$fnAdd($entity);
}
}
The way I call it to update my doctrine association $parentEntity->getPayments() is:
ArrayHelper::syncArrays($parentEntity->getPayments()->toArray(), $newPayments,
function($entity) {return $a->getName();}, // hash function
function($current, $new) {
$current->setTotal($new->getTotal()); // update function
},
function($a) use ($parent, $manager) {
$parent->addVendorPaymentObject($a); // add function
$manager->persist($a);
},
function($a) use ($manager) { // delete function
$manager->remove($a);
}
);