我真的没有发现正常的PHP文件的例子,MySQL事务正在使用。你能举个简单的例子吗?
还有一个问题。我已经做过很多编程,没有使用过事务。我能不能在header。PHP中放一个PHP函数,如果一个mysql_query失败了,那么其他的也会失败?
我想我已经弄明白了,对吗?:
mysql_query("SET AUTOCOMMIT=0");
mysql_query("START TRANSACTION");
$a1 = mysql_query("INSERT INTO rarara (l_id) VALUES('1')");
$a2 = mysql_query("INSERT INTO rarara (l_id) VALUES('2')");
if ($a1 and $a2) {
mysql_query("COMMIT");
} else {
mysql_query("ROLLBACK");
}
由于这是谷歌上的第一个结果“php mysql事务”,我想我应该添加一个答案,显式地演示如何使用mysqli(原作者想要的例子)。下面是一个PHP/mysqli事务的简化示例:
// let's pretend that a user wants to create a new "group". we will do so
// while at the same time creating a "membership" for the group which
// consists solely of the user themselves (at first). accordingly, the group
// and membership records should be created together, or not at all.
// this sounds like a job for: TRANSACTIONS! (*cue music*)
$group_name = "The Thursday Thumpers";
$member_name = "EleventyOne";
$conn = new mysqli($db_host,$db_user,$db_passwd,$db_name); // error-check this
// note: this is meant for InnoDB tables. won't work with MyISAM tables.
try {
$conn->autocommit(FALSE); // i.e., start transaction
// assume that the TABLE groups has an auto_increment id field
$query = "INSERT INTO groups (name) ";
$query .= "VALUES ('$group_name')";
$result = $conn->query($query);
if ( !$result ) {
$result->free();
throw new Exception($conn->error);
}
$group_id = $conn->insert_id; // last auto_inc id from *this* connection
$query = "INSERT INTO group_membership (group_id,name) ";
$query .= "VALUES ('$group_id','$member_name')";
$result = $conn->query($query);
if ( !$result ) {
$result->free();
throw new Exception($conn->error);
}
// our SQL queries have been successful. commit them
// and go back to non-transaction mode.
$conn->commit();
$conn->autocommit(TRUE); // i.e., end transaction
}
catch ( Exception $e ) {
// before rolling back the transaction, you'd want
// to make sure that the exception was db-related
$conn->rollback();
$conn->autocommit(TRUE); // i.e., end transaction
}
另外,请记住PHP 5.5有一个新方法mysqli::begin_transaction。但是,PHP团队还没有将其记录下来,我仍然停留在PHP 5.3中,所以我不能对此进行评论。
我在处理事务时通常使用的思想是这样的(半伪代码):
try {
// First of all, let's begin a transaction
$db->beginTransaction();
// A set of queries; if one fails, an exception should be thrown
$db->query('first query');
$db->query('second query');
$db->query('third query');
// If we arrive here, it means that no exception was thrown
// i.e. no query has failed, and we can commit the transaction
$db->commit();
} catch (\Throwable $e) {
// An exception has been thrown
// We must rollback the transaction
$db->rollback();
throw $e; // but the error must be handled anyway
}
Note that, with this idea, if a query fails, an Exception must be thrown:
PDO可以做到这一点,这取决于您如何配置它
看到PDO:: setAttribute
和PDO::ATTR_ERRMODE和PDO::ERRMODE_EXCEPTION
否则,使用一些其他API,您可能必须测试用于执行查询的函数的结果,并自己抛出异常。
Unfortunately, there is no magic involved. You cannot just put an instruction somewhere and have transactions done automatically: you still have to specific which group of queries must be executed in a transaction.
例如,您经常会在事务之前(开始之前)有几个查询,在事务之后(提交或回滚之后)有另外两个查询,您希望无论事务中发生了什么(或没有发生什么),都能执行这些查询。