php mysql 事务回滚疑惑

Question

我对mysql事务有一些疑问。我需要同时在两个不同的表中创建两条记录，如果其中一条插入失败，则不得保存另一条记录。这是我的代码:

$conn->autocommit(FALSE);
$conn->query("START TRANSACTION");

// Insert values 
$conn->query("INSERT INTO cards (id, points, reg_date, last_update) VALUES ('','$points', '$reg_date', '$reg_date')");
$card_id = $conn->insert_id;

$conn->query("INSERT INTO students (id, firstname, lastname, email, telephone, birthdate, address, city, cap, fiscal_code, username, card_id, password, token_password, reg_date, is_active)
    VALUES ('','$student->firstname', '$student->lastname', '$student->email', '$student->telephone', '$student->birthdate', '$student->address', '$student->city', '$student->cap', '$student->fiscal_code', '$student->username', '$card_id','$student->password', '$student->token_password', '$student->reg_date', '$student->is_active')");

// Commit transaction
if (!$conn->commit()) {
    print("Transaction commit failed\n");
    $conn->rollback();
}   
$conn->close();

$conn 链接是在包含的文件中创建的，我需要 $card_id 因为它是第二个查询的值中的外键。问题是:如果第一个查询失败，一切正常，因此我的数据库中不会插入任何记录。但是，如果第二个查询失败，则回滚不起作用，第一个查询的记录将保存在数据库中。编辑:我正在使用 InnoDB。我哪里做错了？谢谢。

Answer 1

首先确保您的数据库引擎是InnoDB。

function begin(){
mysql_query("BEGIN");
}

function commit(){
mysql_query("COMMIT");
}

function rollback(){
mysql_query("ROLLBACK");
}

mysql_connect("localhost","root", "") or die(mysql_error());

mysql_select_db("test") or die(mysql_error());

begin(); // transaction begins
// Insert values 
 mysql_query("INSERT INTO cards (id, points, reg_date, last_update) VALUES ('','$points', '$reg_date', '$reg_date')");
 $card_id = $conn->insert_id;

 mysql_query("INSERT INTO students (id, firstname, lastname, email, telephone, birthdate, address, city, cap, fiscal_code, username, card_id, password, token_password, reg_date, is_active)
 VALUES ('','$student->firstname', '$student->lastname', '$student->email', '$student->telephone', '$student->birthdate', '$student->address', '$student->city', '$student->cap', '$student->fiscal_code', '$student->username', '$card_id','$student->password', '$student->token_password', '$student->reg_date', '$student->is_active')");


$result = mysql_query($query);

if(!$result){
rollback(); // transaction rolls back
echo "transaction rolled back";
exit;
}else{
commit(); // transaction is committed
echo "Database transaction was successful";
}

?>

希望这有帮助。