code: public function fetchOne($tableName, array $identifier, $shardingKey = null, $forceFromMaster = true)
      {
          return $this->fetch($tableName, $identifier, $shardingKey, array('*'), false, $forceFromMaster);
      }
docs: Fetch one entry from database
  
  @param string $tableName
  @param array  $identifier
  @param null   $shardingKey
  @param bool   $forceFromMaster
  
  @return mixed
  @throws \Exception