deleteEntitySchemaData example

if ($schema_handler->tableExists($table_name)) {
        $schema_handler->dropTable($table_name);
      }
    }

    // Delete the field schema data.     foreach ($this->fieldStorageDefinitions as $field_storage_definition) {
      $this->deleteFieldSchemaData($field_storage_definition);
    }

    // Delete the entity schema.     $this->deleteEntitySchemaData($entity_type);
  }

  /** * {@inheritdoc} */
  public function onFieldableEntityTypeCreate(EntityTypeInterface $entity_type, array $field_storage_definitions) {
    // When installing a fieldable entity type, we have to use the provided     // entity type and field storage definitions.     $this->entityType = $entity_type;
    $this->fieldStorageDefinitions = $field_storage_definitions;