SqlContentEntityStorageSchema::getEntitySchema

protected SqlContentEntityStorageSchema::getEntitySchema(ContentEntityTypeInterface $entity_type, $reset = FALSE)

protected function getEntitySchema(ContentEntityTypeInterface $entity_type, $reset = FALSE) {
  $this->checkEntityType($entity_type);
  $entity_type_id = $entity_type->id();

  if (!isset($this->schema[$entity_type_id]) || $reset) {
    // Back up the storage definition and replace it with the passed one.
    // @todo Instead of switching the wrapped entity type, we should be able
    //   to instantiate a new table mapping for each entity type definition.
    //   See https://www.drupal.org/node/2274017.
    $actual_definition = $this->entityManager->getDefinition($entity_type_id);
    $this->storage->setEntityType($entity_type);

    // Prepare basic information about the entity type.
    $tables = $this->getEntitySchemaTables();

    // Initialize the table schema.
    $schema[$tables['base_table']] = $this->initializeBaseTable($entity_type);
    if (isset($tables['revision_table'])) {
      $schema[$tables['revision_table']] = $this->initializeRevisionTable($entity_type);
    }
    if (isset($tables['data_table'])) {
      $schema[$tables['data_table']] = $this->initializeDataTable($entity_type);
    }
    if (isset($tables['revision_data_table'])) {
      $schema[$tables['revision_data_table']] = $this->initializeRevisionDataTable($entity_type);
    }

    // We need to act only on shared entity schema tables.
    $table_mapping = $this->storage->getTableMapping();
    $table_names = array_diff($table_mapping->getTableNames(), $table_mapping->getDedicatedTableNames());
    $storage_definitions = $this->entityManager->getFieldStorageDefinitions($entity_type_id);
    foreach ($table_names as $table_name) {
      if (!isset($schema[$table_name])) {
        $schema[$table_name] = array();
      }
      foreach ($table_mapping->getFieldNames($table_name) as $field_name) {
        if (!isset($storage_definitions[$field_name])) {
          throw new FieldException("Field storage definition for '$field_name' could not be found.");
        }
        // Add the schema for base field definitions.
        elseif ($table_mapping->allowsSharedTableStorage($storage_definitions[$field_name])) {
          $column_names = $table_mapping->getColumnNames($field_name);
          $storage_definition = $storage_definitions[$field_name];
          $schema[$table_name] = array_merge_recursive($schema[$table_name], $this->getSharedTableFieldSchema($storage_definition, $table_name, $column_names));
        }
      }
    }

    // Process tables after having gathered field information.
    $this->processBaseTable($entity_type, $schema[$tables['base_table']]);
    if (isset($tables['revision_table'])) {
      $this->processRevisionTable($entity_type, $schema[$tables['revision_table']]);
    }
    if (isset($tables['data_table'])) {
      $this->processDataTable($entity_type, $schema[$tables['data_table']]);
    }
    if (isset($tables['revision_data_table'])) {
      $this->processRevisionDataTable($entity_type, $schema[$tables['revision_data_table']]);
    }

    $this->schema[$entity_type_id] = $schema;

    // Restore the actual definition.
    $this->storage->setEntityType($actual_definition);
  }

  return $this->schema[$entity_type_id];
}