mysqli::release_savepoint
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!
mysqli::rollback
mysqli_rollback
(PHP 5)
mysqli::rollback -- mysqli_rollback — Rolls back current transaction
Descrierea
Stil obiect-orientat
bool mysqli::rollback
([ int
$flags
[, string $name
]] )Stil procedural
Rollbacks the current transaction for the database.
Parametri
-
link -
Numai stilul procedural: Un identificator al legăturii întors de mysqli_connect() sau mysqli_init()
-
flags -
A bitmask of
MYSQLI_TRANS_COR_*constants. -
name -
If provided then ROLLBACK/*name*/ is executed.
Valorile întoarse
Întoarce valoarea TRUE în cazul
succesului sau FALSE în cazul eșecului.
Istoria schimbărilor
| Versiunea | Descriere |
|---|---|
| 5.5.0 |
Added flags and name
parameters.
|
Exemple
Example #1 mysqli::rollback() example
Stil obiect-orientat
<?php
$mysqli = new mysqli("localhost", "my_user", "my_password", "world");
/* check connection */
if (mysqli_connect_errno()) {
printf("Connect failed: %s\n", mysqli_connect_error());
exit();
}
/* disable autocommit */
$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");
/* commit insert */
$mysqli->commit();
/* delete all rows */
$mysqli->query("DELETE FROM myCity");
if ($result = $mysqli->query("SELECT COUNT(*) FROM myCity")) {
$row = $result->fetch_row();
printf("%d rows in table myCity.\n", $row[0]);
/* Free result */
$result->close();
}
/* Rollback */
$mysqli->rollback();
if ($result = $mysqli->query("SELECT COUNT(*) FROM myCity")) {
$row = $result->fetch_row();
printf("%d rows in table myCity (after rollback).\n", $row[0]);
/* Free result */
$result->close();
}
/* Drop table myCity */
$mysqli->query("DROP TABLE myCity");
$mysqli->close();
?>
Stil procedural
<?php
$link = mysqli_connect("localhost", "my_user", "my_password", "world");
/* check connection */
if (mysqli_connect_errno()) {
printf("Connect failed: %s\n", mysqli_connect_error());
exit();
}
/* disable autocommit */
mysqli_autocommit($link, FALSE);
mysqli_query($link, "CREATE TABLE myCity LIKE City");
mysqli_query($link, "ALTER TABLE myCity Type=InnoDB");
mysqli_query($link, "INSERT INTO myCity SELECT * FROM City LIMIT 50");
/* commit insert */
mysqli_commit($link);
/* delete all rows */
mysqli_query($link, "DELETE FROM myCity");
if ($result = mysqli_query($link, "SELECT COUNT(*) FROM myCity")) {
$row = mysqli_fetch_row($result);
printf("%d rows in table myCity.\n", $row[0]);
/* Free result */
mysqli_free_result($result);
}
/* Rollback */
mysqli_rollback($link);
if ($result = mysqli_query($link, "SELECT COUNT(*) FROM myCity")) {
$row = mysqli_fetch_row($result);
printf("%d rows in table myCity (after rollback).\n", $row[0]);
/* Free result */
mysqli_free_result($result);
}
/* Drop table myCity */
mysqli_query($link, "DROP TABLE myCity");
mysqli_close($link);
?>
Exemplele de mai sus vor afișa:
0 rows in table myCity. 50 rows in table myCity (after rollback).
Vedeți de asemenea
- mysqli_begin_transaction() - Starts a transaction
- mysqli_commit() - Commits the current transaction
- mysqli_autocommit() - Turns on or off auto-committing database modifications
- mysqli_release_savepoint() - Rolls back a transaction to the named savepoint
add a note
User Contributed Notes
mysqli::rollback - [4 notes]
Lorenzo - webmaster AT 4tour DOT it ¶
4 years ago
xcalibur at xcalibur dot dk ¶
3 years ago
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.
jd at dilltree dot com ¶
3 years ago
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.
Steven McCoy ¶
1 year ago
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