How to properly delete a field collection?

Question

Drupal version: 7.21
Field collection module version: 7.x-1.0-beta5

Short explanation: I'm busy trying to import field collections programmatically but when deleting some of them there's always some 'bogus' field collection left.

Long explanation: My users have a field collection field on their profile. This field collection contains 3 text fields. I want to import data from a custom sql database into the field collection of the user. This field collection can have multiple values. When I import the data for the first time everything works fine, I see the data in the fields of the field collection. Great.

But here comes the tricky part. Let's say I import for one specific user 5 rows from the custom database. They get added to the field collection, so this field collection has 5 items each containing 3 fields. Then I delete some rows from my custom database so that I have only 3 rows left for this user. I run the import again, updating the first 3 items of the field collection, but then I'm left with 2 items from the previous import. They should be deleted because I have only 3 imported rows but still 5 field collection items.

So I tried to delete these field collection items, but there's always one or more items left. The fields are empty when I look at the user profile but there's still something there. Let's say at this point I add 5 new rows for the user in my custom database, so I have 8 rows in total for this user. Then I run the import again. The first 3 items get updated, but then when I try to add the 4th row it still gets an entity id from the 4th field collection item, tries to update it but fails and returns this error:

 Fatal error: Call to undefined method stdClass::save()

I tried deleting the field collection items with each of these methods below:

// Method 1
entity_delete_multiple('field_collection_item', array($fc_id));

// Method 2
$field_collection_item = field_collection_item_load($fc_id);
$field_collection_item->delete();

// Method 3
$field_collection_item = field_collection_item_load($fc_id);
$field_collection_item->deleteRevision();

This is my full code:

function import_user_field_collection(&$user, $old_user_id) {

  // I do a query to get the rows I want to import for this specific user.
  db_set_active('custom_sql_database');
  $result = db_query("SELECT * FROM {users} WHERE user_id = :user_id", array(':user_id' => $old_user_id));

  db_set_active('default');
  $i = 0; // Keep count of how many rows I imported.
  foreach($result as $row) {
    // Check if the field collection item already exists.
    if(!empty($user->field_profile_diploma_opleiding[LANGUAGE_NONE][$i]['value'])) {
      // If it does exists, update this particular field collection item.
      $fc_id = $user->field_profile_diploma_opleiding[LANGUAGE_NONE][$i]['value'];
      $field_collection_item = entity_load('field_collection_item', array($fc_id));
      // These 3 text fields are children of the field collection field.
      $field_collection_item[$fc_id]->field_profile_diploma_instituut[LANGUAGE_NONE][0]['value'] = $row->instituut;
      $field_collection_item[$fc_id]->field_profile_diploma_vakgebied[LANGUAGE_NONE][0]['value'] = $row->vakgebied;
      $field_collection_item[$fc_id]->field_profile_diploma_jaar[LANGUAGE_NONE][0]['value'] = $row->jaar_diploma;
      $field_collection_item[$fc_id]->save(TRUE);
    } else {
      // If the field collection item doesn't exist I want to create a new field collection item.
      $field_collection_item = entity_create('field_collection_item', array('field_name' => 'field_profile_diploma_opleiding'));
      $field_collection_item->setHostEntity('user', $user);
      $field_collection_item->field_profile_diploma_instituut[LANGUAGE_NONE][0]['value'] = $row->instituut;
      $field_collection_item->field_profile_diploma_vakgebied[LANGUAGE_NONE][0]['value'] = $row->vakgebied;
      $field_collection_item->field_profile_diploma_jaar[LANGUAGE_NONE][0]['value'] = $row->jaar_diploma;
      $field_collection_item->save(TRUE);
    }
    $i++;
  }

  $fc_fields = field_get_items('user', $user, 'field_profile_diploma_opleiding');

  // Check if there are more field collection items than imported rows
  if(count($fc_fields) > $i) {
    for($i; $i <= count($fc_fields); $i++) {
      // Run through each field collection item that's left from the previous import and delete it.
      if(!empty($user->field_profile_diploma_opleiding[LANGUAGE_NONE][$i]['value'])) {
        // Method 1
        $fc_id = $user->field_profile_diploma_opleiding[LANGUAGE_NONE][$i]['value'];
        entity_delete_multiple('field_collection_item', array($fc_id));

        // Method 2
        //$field_collection_item = field_collection_item_load($fc_id);
        //$field_collection_item->delete();

        // Method 3
        //$field_collection_item = field_collection_item_load($fc_id);
        //$field_collection_item->deleteRevision();
      }
    }
  }
}

So my question is: How do I delete field collection items so that they're actually gone?

Answer 1

I ran into a similar use case where I wanted to map some data into a field collection during hook_feeds_presave() since the source structure was too complex for Feeds. I found that entity_delete_multiple() removed the field collection items, but when I edited the node, there were still a bunch of empty field collection there. Unsetting and deleting did the trick, which I found here: https://drupal.stackexchange.com/a/31820/2762

If the feeds source has changed, I delete all field collection items and recreate. Hope this is helpful.

foreach ($node->field_international_activity[LANGUAGE_NONE] as $key => $value) {
  // Build array of field collection values.
  $field_collection_item_values[] = $value['value'];

  // Unset them.  
  unset($node->field_international_activity[LANGUAGE_NONE][$key]);
}

// Delete field collection items.
entity_delete_multiple('field_collection_item', $field_collection_item_values);

Answer 2

The best way to do this now is call $field_collection->delete() and that will handle everything.

 <?php
    /**
     * Deletes the field collection item and the reference in the host entity.
     */
    public function delete() {
      parent::delete();
      $this->deleteHostEntityReference();
    }

    /**
     * Deletes the host entity's reference of the field collection item.
     */
    protected function deleteHostEntityReference() {
      $delta = $this->delta();
      if ($this->item_id && isset($delta)) {
        unset($this->hostEntity->{$this->field_name}[$this->langcode][$delta]);
        entity_save($this->hostEntityType, $this->hostEntity);
      }
    }
 ?>

Answer 3

The above answers are not the best way, with unset all the other items disappeared fron the field collection, and the other way with ->delete() throws a bug with the Entity module.

Correct way. Well what I did was this:

In my case I wanted to delete the last item within the field collection

take a look to this code, (for beginers: "remember that you must have the $entity already loaded")

// Remove the field value
unset($entity->field_salida_mercanc_a[LANGUAGE_NONE][count($entity->field_salida_mercanc_a[LANGUAGE_NONE])-1]);

// Reset the array to zero-based sequential keys
$entity->field_salida_mercanc_a[LANGUAGE_NONE] = array_values($entity->field_salida_mercanc_a[LANGUAGE_NONE]);

// Save the entity
entity_save($entity_type, $entity);

thats all! the other way is

//Get the node wapper
$wrapper = entity_metadata_wrapper($entity_type, $entity);
//Get the last position of the array items, thanks to the ->value() statement you can get the complete Array properties.
$field_collection_item_value = $wrapper->field_collection_mine[count($wrapper->field_collection_mine->value())-1]->value();
//Do not use 'unset' to delete the item due to is not the correct way, I use the entity_delete_multiple provided by the entity API
entity_delete_multiple('field_collection_item', array($field_collection_item_value->item_id));

The way above is good using entity_metadata_wrapper function but with that way there is a complex bug that I do not know how to solve it, you can check it at https://drupal.org/node/1880312 and after apply the patch in #9 you get the next issue, check it here https://drupal.org/node/2186689 this bug is also if you use ->delete() function.

Hope it helps someone.

Answer 4

using vbo to delete the field collection items. it will auto remove the field relation with the field collection item host entity.

Answer 5

I had a similar issue, where I am importing data from a feed into a FC item. When an update to a host entity is made from the feed, and I'm importing those changes, I wanted to ensure that any existing FC items that no longer exist from the feed source were removed.

My solution:

// Load host entity that I'm updating.
$host_entity = node_load($nid);
$host_entity_wrapper = entity_metadata_wrapper('node', $host_entity);

// Clear out the references to the existing FC items so that I have a fresh start.
$host_entity_wrapper->field_my_fc_items->set(NULL);

// Re-create the FC items from the source feed data.
foreach ($feed_data->items as $feed_item) {
  $fc = entity_create('field_collection_item', array('field_name' => 'field_my_fc_items'));
  $fc->setHostEntity($host_entity);
  // Some some fields on the FC item from the feed data.
  $fc_wrapper = entity_metadata_wrapper('field_collection_item', $fc);
  $fc_wrapper->field_some_fc_item_field->set($feed_item->data);
}

// Sync other field info onto host entity.
...

$host_entity_wrapper->save();

And that's it. Field Collection's hook_field_update (field_collection_field_update) will take care of actually deleting any existing FC items that have been de-referenced.

The only downside to this is if there was no change in the FC data, it's deleted and re-created anyway. But that's not a big deal for me.