据我所知，一旦我们调用$mysqli->autocommit(FALSE);语句就会启动事务，并在调用$mysqli->commit();命令后结束，如下例所示。
<?php
//Start transaction
$mysqli->autocommit(FALSE);
$mysqli->query('UPDATE `table` SET `col`=2');
$mysqli->query('UPDATE `table1` SET `col1`=3;');
$mysqli->commit();
//End transaction
//Executing other queries without transaction control
$mysqli->query("Select * from table1");
$mysqli->query("Update table1 set col1=2");
//End of executing other queries without transaction control
//Start transaction
$mysqli->autocommit(FALSE);
$mysqli->query('UPDATE `table` SET `col`=2');
$mysqli->query('UPDATE `table1` SET `col1`=3;');
$mysqli->commit();
//End transaction
?>
我理解正确吗？如果没有，请你纠正我，因为这实际上是我第一次在现实生活中使用交易。
谢谢。
答案 0 :(得分：27)
根据the php doc，你是对的。
<?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();
}
$mysqli->query("CREATE TABLE Language LIKE CountryLanguage");
/* set autocommit to off */
$mysqli->autocommit(FALSE);
/* Insert some values */
$mysqli->query("INSERT INTO Language VALUES ('DEU', 'Bavarian', 'F', 11.2)");
$mysqli->query("INSERT INTO Language VALUES ('DEU', 'Swabian', 'F', 9.4)");
/* commit transaction */
$mysqli->commit();
/* drop table */
$mysqli->query("DROP TABLE Language");
/* close connection */
$mysqli->close();
?>
在上面的示例中：
CREATE TABLE是自动提交的，因为它是默认行为。INSERT INTO，autocommit(FALSE) 未自动提交。DROP TABLE自动提交，因为autocommit(FALSE) ->commit(); 重置。答案 1 :(得分：27)
j0k主要是正确的，除了丢弃表。
使用 - ＆gt; commit（）
未启用自动提交相反，DROP TABLE是一个DDL查询，DDL查询总是隐式提交，并且将提交所有以前未提交的工作。
因此，如果您未提交工作，则DDL查询将强制执行此提交。
答案 2 :(得分：12)
准备SQL语句ONCE，然后执行它几次：
<?php
$Mysqli = new mysqli("host","user","pass","base");
// check connection
if(mysqli_connect_errno())
{
printf("Connect failed: %s\n",mysqli_connect_error());
exit();
}
// some data for db insertion
$countries=['Austria','Belgia','Croatia','Denmark','Estonia'];
// explicitly begin DB transaction
$Mysqli->begin_transaction();
// prepare statement (for multiple inserts) only once
$stmt=$Mysqli->prepare("INSERT INTO table(column) VALUES(?)");
// bind (by reference) prepared statement with variable $country
$stmt->bind_param('s',$country);
// load value from array into referenced variable $country
foreach($countries as $country)
{
//execute prep stat more times with new values
//$country is binded (referenced) by statement
//each execute will get new $country value
if(!$stmt->execute())
{
// rollback if prep stat execution fails
$Mysqli->rollback();
// exit or throw an exception
exit();
}
}
// close prepared statement
$stmt->close();
// commit transaction
$Mysqli->commit();
// close connection
$Mysqli->close();
?>
答案 3 :(得分：10)
为了使事务正常运行，您应该启用异常错误报告。否则，mysqli将不会报告错误，并且交易将无法正确执行。或者，您可以手动检查每个查询，但是不建议这样做。要正确连接mysqli，请使用以下3行：
mysqli_report(MYSQLI_REPORT_ERROR | MYSQLI_REPORT_STRICT);
$mysqli = new mysqli('localhost', 'user', 'pass', 'dbname');
$mysqli->set_charset('utf8mb4'); // always set the charset
有两种使用mysqli创建事务的可能方法。默认情况下，所有查询/语句一执行即被提交。您可以关闭自动提交功能，也可以使用一次性交易。
在以下情况下，事务将提交给数据库：
commit时如果您关闭了自动提交功能，则可以决定何时提交，但是调用commit()并不会重新打开自动提交功能。
//Start transaction
$mysqli->autocommit(false);
$mysqli->query('INSERT INTO director(name) VALUE("Steven Spielberg")');
$directorId = $mysqli->insert_id;
$movieTitle = 'Jurassic Park';
$stmt = $mysqli->prepare('INSERT INTO movie(title, directorId) VALUE(?,?)');
$stmt->bind_param('ss', $movieTitle, $directorId);
$stmt->execute();
$mysqli->commit();
// Changes are committed, but autocommit is not switched back on
// Following queries are still transactional. They will not be committed unless you call commit or switch autocommit back on
$mysqli->query('INSERT INTO director(name) VALUE("James Cameron")');
$directorId = $mysqli->insert_id;
$movieTitle = 'Titanic';
$stmt = $mysqli->prepare('INSERT INTO movie(title, directorId) VALUE(?,?)');
$stmt->bind_param('ss', $movieTitle, $directorId);
$stmt->execute();
$mysqli->autocommit(true);
// All queries are committed and everything that follows will be immediately committed.
您可以使用begin_transaction()进行一次性交易。这不会设置autocommit=false，因此当您致电commit()时，无需开始新交易即可结束交易。
//Start transaction
$mysqli->begin_transaction();
$mysqli->query('INSERT INTO director(name) VALUE("Steven Spielberg")');
$directorId = $mysqli->insert_id;
$movieTitle = 'Jurassic Park';
$stmt = $mysqli->prepare('INSERT INTO movie(title, directorId) VALUE(?,?)');
$stmt->bind_param('ss', $movieTitle, $directorId);
$stmt->execute();
$mysqli->commit();
// Changes are committed and the transaction has ended
// Following queries will be committed one by one as soon as they are peformed.
$mysqli->query('INSERT INTO director(name) VALUE("James Cameron")');
$directorId = $mysqli->insert_id;
$movieTitle = 'Titanic';
$stmt = $mysqli->prepare('INSERT INTO movie(title, directorId) VALUE(?,?)');
$stmt->bind_param('ss', $movieTitle, $directorId);
$stmt->execute();
某些SQL语句触发显式提交，但不影响autocommit的值。
//Start transaction
$mysqli->autocommit(false);
$mysqli->query('INSERT INTO director(name) VALUE("Steven Spielberg")');
$directorId = $mysqli->insert_id;
$movieTitle = 'Jurassic Park';
$stmt = $mysqli->prepare('INSERT INTO movie(title, directorId) VALUE(?,?)');
$stmt->bind_param('ss', $movieTitle, $directorId);
$stmt->execute();
// The following will call commit but it will not set autocommit=true
$mysqli->query('TRUNCATE TABLE movie_genre');
// if you want to switch autocommit back on, you have to call:
$mysqli->autocommit(true);
如果发生异常，则PHP将终止脚本的执行，并且代码将永远不会到达commit语句。但是，在某些情况下，您可能希望显式回滚事务，例如，以避免在代码的其他地方意外调用commit。
以下是此类交易的示例。第二个查询试图插入到不存在的表中，这意味着mysqli将抛出异常。我们捕获异常并回滚事务，而不是让PHP脚本死亡。值4将永远不会插入数据库中，因为两个查询都已回滚。
try {
// Start transaction
$mysqli->begin_transaction();
$mysqli->query('INSERT INTO some_table(col2) VALUE(4)');
$mysqli->query('INSERT INTO does_not_exist(col2) VALUE(4)');
// Commit changes
$mysqli->commit();
} catch (\Throwable $e) {
// Something went wrong. Rollback
$mysqli->rollback();
// Rethrow the exception so that PHP does not continue with the execution and the error can be logged in the error_log
throw $e;
}
答案 4 :(得分：8)
您认为命令“commit”会自动将autocommit切换回true吗？ php doc中的评论说不！