CollectionFind::lockExclusive

Execute operation with EXCLUSIVE LOCK

Description

public mysql_xdevapi\CollectionFind mysql_xdevapi\CollectionFind::lockExclusive(int $lock_waiting_option = ?)

Locks the document exclusively. As long as the document is locked, other transactions can't update the document, use SELECT ... LOCK IN SHARE MODE, or read the data in certain transaction isolation levels. Consistent reads ignore any locks set on the records that exist in the read view.

To avoid concurrency problems, it makes sense to use this function with the mysql_xdevapi\Collection::modify method. Essentially, this function uses row locks to serialise access to rows.

Parameters

lock_waiting_option

Optional waiting option. By default it is MYSQLX_LOCK_DEFAULT. Valid values are these constants:

MYSQLX_LOCK_DEFAULT
MYSQLX_LOCK_NOWAIT
MYSQLX_LOCK_SKIP_LOCKED

Return Values

Returns a CollectionFind object that can be used for further processing.

Examples

Example #1 mysql_xdevapi\CollectionFind::lockExclusive example

<?php
$session = mysql_xdevapi\getSession("mysqlx://user:password@localhost");

$schema     = $session->getSchema("addressbook");
$collection = $schema->createCollection("people");

$session->startTransaction();

$result = $collection
  ->find("age > 50")
  ->lockExclusive()
  ->execute();

// ... do an operation on the object

// Complete the transaction and unlock the document
$session->commit();
?>