field_sql_storage.install

<?php
/**
 * @file
 * Install, update and uninstall functions for the field_sql_storage module.
 */

/**
 * Implements hook_schema().
 */
function field_sql_storage_schema() {
  $schema = array();

  // Dynamic (data) tables.
  backdrop_load('module', 'field_sql_storage');
  module_load_include('inc', 'field', 'field.crud');
  $fields = field_read_fields(array(), array('include_deleted' => TRUE, 'include_inactive' => TRUE));
  foreach ($fields as $field) {
    if ($field['storage']['type'] == 'field_sql_storage') {
      $schema += _field_sql_storage_schema($field);
    }
  }

  return $schema;
}

/**
 * Utility function: write field data directly to SQL storage.
 *
 * @ingroup update-api-7.x-to-1.x
 */
function _update_7000_field_sql_storage_write($entity_type, $bundle, $entity_id, $revision_id, $field_name, $data) {
  $table_name = "field_data_{$field_name}";
  $revision_name = "field_revision_{$field_name}";

  db_delete($table_name)
    ->condition('entity_type', $entity_type)
    ->condition('entity_id', $entity_id)
    ->execute();
  db_delete($revision_name)
    ->condition('entity_type', $entity_type)
    ->condition('entity_id', $entity_id)
    ->condition('revision_id', $revision_id)
    ->execute();

  $columns = array();
  foreach ($data as $langcode => $items) {
    foreach ($items as $delta => $item) {
      $record = array(
        'entity_type' => $entity_type,
        'entity_id' => $entity_id,
        'revision_id' => $revision_id,
        'bundle' => $bundle,
        'delta' => $delta,
        'language' => $langcode,
      );
      foreach ($item as $column => $value) {
        $record[_field_sql_storage_columnname($field_name, $column)] = $value;
      }

      $records[] = $record;
      // Record the columns used.
      $columns += $record;
    }
  }

  if ($columns) {
    $query = db_insert($table_name)->fields(array_keys($columns));
    $revision_query = db_insert($revision_name)->fields(array_keys($columns));
    foreach ($records as $record) {
      $query->values($record);
      if ($revision_id) {
        $revision_query->values($record);
      }
    }
    $query->execute();
    $revision_query->execute();
  }
}