Remember that MyISAM tables do not support rollbacks.
I just drove myself crazy for an afternoon trying to figure out what was wrong with my code - meanwhile it was fine all along
(PHP 5, PHP 7)
mysqli::rollback -- mysqli_rollback — Откат текущей транзакции
Объектно-ориентированный стиль
$flags
= 0
[, string $name
]] ) : boolПроцедурный стиль
Откатывает текущую транзакцию.
link
Только для процедурного стиля: Идентификатор соединения, полученный с помощью mysqli_connect() или mysqli_init()
flags
Битовая маска констант MYSQLI_TRANS_COR_*
.
name
Если передана, то выполняется ROLLBACK/*name*/.
Возвращает TRUE
в случае успешного завершения или FALSE
в случае возникновения ошибки.
Версия | Описание |
---|---|
5.5.0 |
Добавлены параметры flags и name .
|
Пример #1 Пример использования mysqli::rollback()
Объектно-ориентированный стиль
<?php
$mysqli = new mysqli("localhost", "my_user", "my_password", "world");
/* проверка соединения */
if (mysqli_connect_errno()) {
printf("Не удалось подключиться: %s\n", mysqli_connect_error());
exit();
}
/* выключаем автофиксацию */
$mysqli->autocommit(FALSE);
$mysqli->query("CREATE TABLE myCity LIKE City");
$mysqli->query("ALTER TABLE myCity Type=InnoDB");
$mysqli->query("INSERT INTO myCity SELECT * FROM City LIMIT 50");
/* фиксируем вставленные строки */
$mysqli->commit();
/* удаляем все строки */
$mysqli->query("DELETE FROM myCity");
if ($result = $mysqli->query("SELECT COUNT(*) FROM myCity")) {
$row = $result->fetch_row();
printf("%d строк в таблице myCity.\n", $row[0]);
/* очищаем результат */
$result->close();
}
/* откат */
$mysqli->rollback();
if ($result = $mysqli->query("SELECT COUNT(*) FROM myCity")) {
$row = $result->fetch_row();
printf("%d строк в таблице myCity (after rollback).\n", $row[0]);
/* очищаем результат */
$result->close();
}
/* удаляем таблицу myCity */
$mysqli->query("DROP TABLE myCity");
$mysqli->close();
?>
Процедурный стиль
<?php
$link = mysqli_connect("localhost", "my_user", "my_password", "world");
/* проверка соединения */
if (mysqli_connect_errno()) {
printf("Не удалось подключиться: %s\n", mysqli_connect_error());
exit();
}
/* выключаем автофиксацию */
mysqli_autocommit($link, FALSE);
mysqli_query($link, "CREATE TABLE myCity LIKE City");
mysqli_query($link, "ALTER TABLE myCity Type=InnoDB");
mysqli_query($link, "INSERT INTO myCity SELECT * FROM City LIMIT 50");
/* фиксируем вставленные строки */
mysqli_commit($link);
/* удаляем все строки */
mysqli_query($link, "DELETE FROM myCity");
if ($result = mysqli_query($link, "SELECT COUNT(*) FROM myCity")) {
$row = mysqli_fetch_row($result);
printf("%d строк в таблице myCity.\n", $row[0]);
/* очищаем результат */
mysqli_free_result($result);
}
/* откат */
mysqli_rollback($link);
if ($result = mysqli_query($link, "SELECT COUNT(*) FROM myCity")) {
$row = mysqli_fetch_row($result);
printf("%d строк в таблице myCity (после отката).\n", $row[0]);
/* очищаем результат */
mysqli_free_result($result);
}
/* удаляем таблицу myCity */
mysqli_query($link, "DROP TABLE myCity");
mysqli_close($link);
?>
Результат выполнения данных примеров:
0 строк в таблице myCity. 50 строк в таблице myCity (после отката).
Remember that MyISAM tables do not support rollbacks.
I just drove myself crazy for an afternoon trying to figure out what was wrong with my code - meanwhile it was fine all along
This is an example to explain the powerful of the rollback and commit functions.
Let's suppose you want to be sure that all queries have to be executed without errors before writing data on the database.
Here's the code:
<?php
$all_query_ok=true; // our control variable
//we make 4 inserts, the last one generates an error
//if at least one query returns an error we change our control variable
$mysqli->query("INSERT INTO myCity (id) VALUES (100)") ? null : $all_query_ok=false;
$mysqli->query("INSERT INTO myCity (id) VALUES (200)") ? null : $all_query_ok=false;
$mysqli->query("INSERT INTO myCity (id) VALUES (300)") ? null : $all_query_ok=false;
$mysqli->query("INSERT INTO myCity (id) VALUES (100)") ? null : $all_query_ok=false; //duplicated PRIMARY KEY VALUE
//now let's test our control variable
$all_query_ok ? $mysqli->commit() : $mysqli->rollback();
$mysqli->close();
?>
hope to be helpful!
Just a note about auto incremental ids and rollback.
When using transactions and inserting into a table containing a column with auto incremental ids, the id will be incremented even though the transaction is rolled back.
This might occupy a lot of ids if a lot of rollbacks are performed.
Example:
<?php
$mysqli = new mysqli("localhost", "gugbageri", "gugbageri", "gugbageri");
/* check connection */
if (mysqli_connect_errno()) {
printf("Connect failed: %s\n", mysqli_connect_error());
exit();
}
/* disable autocommit */
$mysqli->autocommit(FALSE);
/* We just create a test table with one auto incremental primary column and a content column*/
$mysqli->query("CREATE TABLE TestTable ( `id_column` INT NOT NULL AUTO_INCREMENT , `content` INT NOT NULL , PRIMARY KEY ( `id_column` )) ENGINE = InnoDB;");
/* commit newly created table */
$mysqli->commit();
/* we insert a row */
$mysqli->query("INSERT INTO TestTable (content) VALUES (99)");
/* we commit the inserted row */
$mysqli->commit();
/* we insert another three rows */
$mysqli->query("INSERT INTO TestTable (content) VALUES (99)");
$mysqli->query("INSERT INTO TestTable (content) VALUES (99)");
$mysqli->query("INSERT INTO TestTable (content) VALUES (99)");
/* we the rollback */
$mysqli->rollback();
/* we insert a row */
$mysqli->query("INSERT INTO TestTable (content) VALUES (99)");
/* we commit the inserted row */
$mysqli->commit();
if ($result = $mysqli->query("SELECT id_column FROM TestTable")) {
while($row = $result->fetch_row()) {
printf("Id: %d.\n", $row[0]);
}
/* Free result */
$result->close();
}
/* Drop table TestTable */
$mysqli->query("DROP TABLE TestTable");
$mysqli->close();
?>
This will output:
Id: 1.
Id: 5.
Something to consider when using transact is that you should not perform a normal query on the same table (such as a DELETE) immediately after a transaction. If the transaction rolls-back, the DELETE will execute and even show affected rows, but the row can be magically re-inserted even if the rollback() command comes before the DELETE query.