Why is the programmatically removed paragraph item still showing after adding a new paragraph to the node?

Question

I have a paragraph field in a node with unlimited add paragraph. I am removing these paragraph programatically. Its removing but when I am adding a new paragraph its adding blank paragraph along with.

I am using this code to remove paragraph

use Drupal\paragraphs\ParagraphInterface;
use Drupal\paragraphs\Entity\Paragraph;

$ids = \Drupal::entityQuery('paragraph')->execute();
foreach ($ids as $id) {
  $paragraph = Paragraph::load($id);
  if ($paragraph instanceof ParagraphInterface) {
    $paragraph->delete();
  }
}

Answer 1

You have 3 tables doing the job: a table which stores node data, a table which stores paragraphs data, and a table which stores relation about node and paragraphs. Now you emptied the table which stores the paragraphs data, but the node-paragraph relation table is still there. So if you have added 4 paragraphs to a node and deleted that 4 paragraphs, still drupal assumes there should be 4 paragraphs attached to that node.

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so if you want to delete them entirely you have to fetch node data which has "paragraph" field value, delete field value from each node and save it.

so here are steps : you can run a database query on field table, and get all node-paragraph relations. now you have a list of all nodes that have a paragraphs, so having node ids and paragraph ids you can first remove paragraphs from node using a code like this:

$node = Node::load($nid);
$node->FIELD_NAME->setValue(array());
$node->save();

and then delete correspond paragraphs using a code like the one you mentioned. of course you don't need another query as you have paragraph ids.

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if you don't mind removing all paragraph values from database and only don't like them to be shown in your node, then you can write an entityquery like this :

$query = \Drupal::entityQuery('node');
$query->exists('field_to_check');//Check A field value is NOT NULL
$ids = $query->execute();

so it gives you all nodes which has value for that field, then you only can run :

foreach($ids as $nid) {
  $node = Node::load($nid);
  $node->FIELD_NAME->setValue(array());
  $node->save();
}