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。
<?php
// trans.php
function begin(){
mysql_query("BEGIN");
}
function commit(){
mysql_query("COMMIT");
}
function rollback(){
mysql_query("ROLLBACK");
}
mysql_connect("localhost","Dude1", "SuperSecret") or die(mysql_error());
mysql_select_db("bedrock") or die(mysql_error());
$query = "INSERT INTO employee (ssn,name,phone) values ('123-45-6789','Matt','1-800-555-1212')";
begin(); // transaction begins
$result = mysql_query($query);
if(!$result){
rollback(); // transaction rolls back
echo "transaction rolled back";
exit;
}else{
commit(); // transaction is committed
echo "Database transaction was successful";
}
?>
使用PDO连接时:
$pdo = new PDO('mysql:host=localhost;dbname=mydb;charset=utf8', $user, $pass, [
PDO::ATTR_ERRMODE => PDO::ERRMODE_EXCEPTION, // this is important
]);
我经常使用以下代码进行事务管理:
function transaction(Closure $callback)
{
global $pdo; // let's assume our PDO connection is in a global var
// start the transaction outside of the try block, because
// you don't want to rollback a transaction that failed to start
$pdo->beginTransaction();
try
{
$callback();
$pdo->commit();
}
catch (Exception $e) // it's better to replace this with Throwable on PHP 7+
{
$pdo->rollBack();
throw $e; // we still have to complain about the exception
}
}
使用的例子:
transaction(function()
{
global $pdo;
$pdo->query('first query');
$pdo->query('second query');
$pdo->query('third query');
});
这样,事务管理代码就不会在整个项目中重复。这是一件好事,因为从这篇文章中其他与pdo相关的回答来看,它很容易犯错误。最常见的错误是忘记重新抛出异常,并在try块中启动事务。