VersionPress\Database\DbSchemaInfo::isChildEntity PHP Method

    public function isChildEntity($entityName)
    {
        return $this->isEntity($entityName) && $this->getEntityInfo($entityName)->parentReference !== null;
    }

 /**
  * @param $entityName
  * @return mixed
  */
 private function getEntitiesFromDatabase($entityName)
 {
     if ($this->dbSchema->isChildEntity($entityName)) {
         $entityInfo = $this->dbSchema->getEntityInfo($entityName);
         $parentReference = $entityInfo->parentReference;
         return $this->database->get_results("SELECT * FROM {$this->dbSchema->getPrefixedTableName($entityName)} ORDER BY {$parentReference}", ARRAY_A);
     }
     return $this->database->get_results("SELECT * FROM {$this->dbSchema->getPrefixedTableName($entityName)}", ARRAY_A);
 }