#mixed pq\Gateway\Row::ofWhich(mixed $foreign[, string $ref = NULL])

Find the parent row by foreign key. See pq\Gateway\Table::by().

Params:#

• mixed $foreign#
  The foreign table (name).
• Optional string $ref# = NULL
  A specific relation name if there are more than one foreign keys to the same table.

Returns:#

• a deferred promise of React/Promise, when using pq\Query\AsyncExecutor, the asynchronous executor.
  Else:
• pq\Result, if pq\Result::$status != pq\Result::TUPLES_OK.
• pq\Result, if the rowset prototype pq\Gateway\Table::$rowset is empty.
• pq\Gateway\Rowset, an instance of the rowset prototype.