PHP mysqli_rollback MySQLi 函数

mysqli_rollback ( mysqli $link )

$link = mysqli_connect("localhost", "my_user", "my_password", "world");
/* check connection */
if (mysqli_connect_errno()) {
    printf("connect failed: %s\n", mysqli_connect_error());
    exit();
}
/* disable autocommit */
mysqli_autocommit($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);