NodeStorageSchema.php

<?php

namespace Drupal\node;

use Drupal\Core\Entity\ContentEntityTypeInterface;
use Drupal\Core\Entity\Sql\SqlContentEntityStorageSchema;
use Drupal\Core\Field\FieldStorageDefinitionInterface;

/**
 * Defines the node schema handler.
 */
class NodeStorageSchema extends SqlContentEntityStorageSchema {
  
  /**
   * {@inheritdoc}
   */
  protected function getEntitySchema(ContentEntityTypeInterface $entity_type, $reset = FALSE) {
    $schema = parent::getEntitySchema($entity_type, $reset);
    if ($data_table = $this->storage
      ->getDataTable()) {
      $schema[$data_table]['indexes'] += [
        'node__frontpage' => [
          'promote',
          'status',
          'sticky',
          'created',
        ],
        'node__title_type' => [
          'title',
          [
            'type',
            4,
          ],
        ],
      ];
    }
    return $schema;
  }
  
  /**
   * {@inheritdoc}
   */
  protected function getSharedTableFieldSchema(FieldStorageDefinitionInterface $storage_definition, $table_name, array $column_mapping) {
    $schema = parent::getSharedTableFieldSchema($storage_definition, $table_name, $column_mapping);
    $field_name = $storage_definition->getName();
    if ($table_name == 'node_revision') {
      switch ($field_name) {
        case 'langcode':
          $this->addSharedTableFieldIndex($storage_definition, $schema, TRUE);
          break;

        case 'revision_uid':
          $this->addSharedTableFieldForeignKey($storage_definition, $schema, 'users', 'uid');
          break;

      }
    }
    if ($table_name == 'node_field_data') {
      switch ($field_name) {
        case 'promote':
        case 'status':
        case 'sticky':
        case 'title':
          // Improves the performance of the indexes defined
          // in getEntitySchema().
          $schema['fields'][$field_name]['not null'] = TRUE;
          break;

        case 'changed':
        case 'created':
          // @todo Revisit index definitions:
          //   https://www.drupal.org/node/2015277.
          $this->addSharedTableFieldIndex($storage_definition, $schema, TRUE);
          break;

      }
    }
    return $schema;
  }

}