PHP : Function Reference : PDO Functions : PDO->rollBack() PHP Examples Tutorials References

Example 1769. Roll back a transaction

The following example begins a transaction and issues two statements that modify the database before rolling back the changes. On MySQL, however, the DROP TABLE statement automatically commits the transaction so that none of the changes in the transaction are rolled back.

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<?php
/* Begin a transaction, turning off autocommit */
$dbh->beginTransaction();

/* Change the database schema and data */
$sth = $dbh->exec("DROP TABLE fruit");
$sth = $dbh->exec("UPDATE dessert

    SET name = 'hamburger'");

/* Recognize mistake and roll back changes */
$dbh->rollBack();

/* Database connection is now back in autocommit mode */
?>

<?php //run this on your latest PHP let me know if it doesn't fail //to test this program u must run it twice at the same time in ie. two terminals //this program suposedly creates a new dbase with table name NodeNames and one field in it named NodeName //it then begins a transaction then attempts to read an element 'zTest' of field 'NodeName' which obv. doesn't exist, ignoring the returned errors //then it writes it(since it wasn't there) //then decides to rollBack the transaction and eventually try a new one //because rollBack doesn't really work(apparently) for some unknown reason, beginTransaction fails saying 'There is already an active transaction' $db = new PDO('sqlite:demlinks6.3sql',''/*user*/,''/*pwd*/); $db->exec('CREATE TABLE \'NodeNames\' ("NodeName" VARCHAR(10));'); $db->beginTransaction(); $getter="zTest"; $pgn = $db->prepare('SELECT * FROM \'NodeNames\' WHERE "NodeName" = :node13'); $pgn->bindParam(":node13", $getter, PDO::PARAM_STR); //read $pgn->execute();//execute above SELECT $ar=$pgn->FetchAll();//get array of results $writter="zTest"; $pnn=$db->prepare('INSERT INTO \'NodeNames\' ("NodeName") VALUES (:node14)'); $pnn->bindParam(":node14", $writter, PDO::PARAM_STR); //write $pnn->execute();//write it! echo "waiting..."; usleep(2000000); echo "done\n"; $db->rollBack();//this doesn't do it's job $db->beginTransaction();//here it fails, when running this program twice at the same time; 'There is already an active transaction' //unreachable: $db->commit(); ?>

PDO->rollBack()

Rolls back a transaction ()

Example 1769. Roll back a transaction

Code Examples / Notes » pdo_rollback

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