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On . By CodimTh

in this post, I'll show you how to increase the length of field without losing data in drupal 8.


How to increase the length of field to 255 without losing data.

resize field


use hook_update_N() to chnage the length of field to 255 in database, configuration, and in storage schema. like the example below.



use Drupal\field\Entity\FieldStorageConfig;

 * @param $sandbox
function mymodule_update_90005(&$sandbox) {
  $entity_type = 'node';
  $field_name = 'field_description';
  $field_length = 255;

  $database = \Drupal::database();
  // Resize the main field data table.
  $database->query("ALTER TABLE {$entity_type}__{$field_name} MODIFY {$field_name}_value VARCHAR({$field_length})");
  // Resize the revision field data table.
  $database->query("ALTER TABLE {$entity_type}_revision__{$field_name} MODIFY {$field_name}_value VARCHAR({$field_length})");

  // Update storage schema.
  $storage_key = $entity_type . '.field_schema_data.' . $field_name;
  $storage_schema = \Drupal::keyValue('entity.storage_schema.sql');
  $field_schema = $storage_schema->get($storage_key);
  $field_schema[$entity_type . '__' . $field_name]['fields'][$field_name . '_value']['length'] = $field_length;
  $field_schema[$entity_type . '_revision__' . $field_name]['fields'][$field_name . '_value']['length'] = $field_length;
  $storage_schema->set($storage_key, $field_schema);

  // Update field configuration.
  $config = \Drupal::configFactory()
  $config->set('settings.max_length', $field_length);

  // Update field storage configuration.
  FieldStorageConfig::loadByName($entity_type, $field_name)->save();

  return t('Length of @entity-type.@field-name updated to @field-length', [
    '@entity-type' => $entity_type,
    '@field-name' => $field_name,
    '@field-length' => $field_length,


resized field



Submitted by Justin (not verified) on Fri, 12/13/2019 - 17:25 Permalink

I tried this out, but I'm still getting an error when i run my update saying that data exists. > [error] The SQL storage cannot change the schema for an existing field (field_special_information in product_entity entity) with data. It's in a custom entity, so I don't know if that is somehow making a difference.
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Riadh Rahmi

Senior Web Developer (Drupal & Laravel)

I am a senior web developer, I have experience in planning and developing large scale dynamic web applications especially in Drupal and Laravel.

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